标签归档：glucose

葡萄糖氧化酶检测试剂盒 Glucose Oxidase Assay Kit 货号：K-GLOX Megazyme试剂盒

发表于由
葡萄糖氧化酶检测试剂盒

英文名：Glucose Oxidase Assay Kit

货号：K-GLOX

规格：200 assays (manual) / 2000 assays (microplate)

市场价： 2862元

The Glucose Oxidase assay kit is a simple procedure for the rapid and reliable measurement and analysis of glucose oxidase activity in industrial enzyme preparations and bread improver mixtures.

Glucose Oxidase assay kit is suitable for manual, auto-analyser and microplate formats.
 

Colourimetric method for the determination of Glucose Oxidase
in foodstuffs and fermentation products

Principle:
(glucose oxidase)
(1) D-Glucose + H2O + O2 → D-glucono-δ-lactone + H2O2

(peroxidase)
(2) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine →
quinoneimine + 4H2O

Kit size:                            200 assays (manual) / 2000 (microplate)
                                         / 1960 (auto-analyser)
Method:                            Spectrophotometric at 510 nm
Reaction time:                   ~ 20 min
Detection limit:                 10 U/L
Application examples: 
Enzyme preparations, and other materials (e.g. biological cultures,
samples, etc.)
Method recognition:          Novel method

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 12 months after preparation
  • Simple format
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included
  • Suitable for manual, microplate and auto-analyser formats

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D-果糖/D-葡萄糖检测试剂盒 D-Fructose/D-Glucose Assay Kit 货号：K-FRUGL Megazyme试剂盒

发表于由
D-果糖/D-葡萄糖检测试剂盒

英文名：D-Fructose/D-Glucose Assay Kit

货号：K-FRUGL

规格：110 assays (manual) / 1100 assays (micropl

市场价： 3604元

分析物意义：非常常见的食物糖分，如从高果糖玉米种提炼的糖浆增补剂 

Megazyme检测试剂盒优点：反应时间快,可选择简单的版式，适用于手工和自动分析仪检测。试剂稳定 

D-Fructose/D-Glucose test kit, an enzymatic UV-method for the measurement and analysis of D-fructose and/or D-glucose in plant and food products.

Extended cofactors stability. Dissolved cofactors stable for > 1 year at 4oC.

UV-method for the determination of D-Fructose and D-Glucose 
in foodstuffs, beverages and other materials

Principle:
                        (hexokinase)
(1) D-Glucose + ATP → G-6-P + ADP

                         (hexokinase)
(2) D-Fructose + ATP → F-6-P + ADP

          (glucose-6-phosphate dehydrogenase)
(3) G-6-P + NADP+ → gluconate-6-phosphate + NADPH + H+

    (phosphoglucose isomerase)
(4) F-6-P             ↔             G-6-P

Kit size:                             110 assays (manual) / 1100 (microplate)
                                           / 1100 (auto-analyser)
Method:                            Spectrophotometric at 340 nm
Reaction time:                  ~ 13 min
Detection limit:                 0.66 mg/L
Application examples: 
Wine, beer, fruit juices, soft drinks, milk, jam, honey, dietetic foods, 
bread, bakery products, candies, desserts, confectionery, ice-cream, 
fruit and vegetables, condiments, tobacco, cosmetics, pharmaceuticals, 
paper and other materials (e.g. biological cultures, samples, etc.)
Method recognition:     
Methods based on this principle have been accepted by AOAC, EN,
NEN, NF, DIN, GOST, OIV, IFU, AIJN, MEBAK and IOCCC

 Q1. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q2. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q3. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample,  in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q4. The calibration curve in the K-FRUGL data booklet is based on using a 4.6 mm pathlength cuvette. The cuvettes I am using have a 10 mm path-length. Do I have to have the 4.6 mm path-length cuvettes or can I use 10 mm path-length cuvettes?

If a spectrophotometer and standard 10 mm path-length cuvettes are being used, then the assay should be performed as described in the data booklet for either of the “Manual Format” methods (individual values of fructose and glucose or total sugars; glucose plus fructose).

These “Manual Format” methods do not require the use of a standard calibration curve and results should be obtained from the calculations as described for the appropriate method used.  Alternatively, results can be processed using the MegaCalc application which can be found where the product is located on the Megazyme website.  This application processes results from simple entry of raw data absorbance values.  The standard calibration curve is purely for use with auto-analyser instruments (e.g. Konelab) where the path-lengths vary from 10 mm and therefore do not permit use of the calculations in the data booklet or the MegaCalc application.

Q5. The pH of my sample is low (pH ~ 3.0), do I need to adjust this before I use the sample in the kit assay?

The final pH of the kit assay after the sample is added should not change from what it should be (as stated in the kit for the assay buffer). If it does change then the sample will require pH adjustment. In most cases the sample volume being used is low relative to the final assay volume and in this case the pH of the kit assay is unlikely to be affected.

Q6. How can I work out how much sample to extract and what dilution of my sample should be used in the kit assay?

Where the amount of analyte in a liquid sample is unknown, it is recommended that a range of sample dilutions are prepared with the aim of obtaining an absorbance change in the assay that is within the linear range.
Where solid samples are analysed, the weight of sample per volume of water used for sample extraction/preparation can be altered to suit, as can the dilution of the extracted sample prior to the addition of the assay, as per liquid samples.

Q7. Can you explain, step by step, how to follow the method and perform the kit assay?

For users who are not familiar with how to use the Megazyme tests kits then it is recommended that they follow this example, e.g. D-Fructose/D-Glucose Assay kit K-FRUGL (http://secure.megazyme.com/D-Fructose-D-Glucose-Assay-Kit):

1. The kit components are listed on pages 2-3 of the kit booklet.
2. Prepare the kit reagents as described on page 3.
3. For separate measurements of glucose and fructose follow procedure A on page 4.
4. Pipette the volumes listed for water, sample, solution 1 and solution 2 into 3 mL, 1 cm pathlength cuvettes. Duplicate sample assays and duplicate blanks are recommended. Mix the contents of each cuvette by inversion (seal the cuvette using parafilm or a plastic cuvette cap – do not use a finger) then after ~3 min record the first absorbance reading of each cuvette at 340 nm (this is reading A1).
5. Then add suspension 3 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then record the absorbance reading of each cuvette at 340 nm (this is reading A2). NB. It is essential that the reaction is compete. To assess this, record the absorbances at ~ 2 minute intervals and until the absorbance plateaus. A stable absorbance indicates that the reaction is complete. If the absorbance continues to increase then continue to record absorbances until it plateaus and only then record absorbance reading A2.
6. Then add suspension 4 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then take absorbance reading of each cuvette at 340 nm (this is reading A3). NB. As above, assess that the reaction has completed by take subsequent readings at ~2 min intervals.
7. For simple, automated results analysis, input the absorbance readings (A1, A2, A3) for samples and blanks into the K-FRUGL MegaCalc.

To ensure that the assay is working, and being performed correctly it is recommend that the test is performed using the standard sample that is provided with the kit and to obtain the expected values before proceeding to test real samples.
It is recommend that new users also watch this video which highlights how to perform the assays.
Many of the other Megazyme test kits follow a similar format.

Q8. I have some doubts about the appearance/quality of a kit component what should be done?

If there are any concerns with any kit components, the first thing to do is to test the standard sample (control sample) that is supplied with the kit and ensure that the expected value (within the accepted variation) is obtained before testing any precious samples. This must be done using the procedure provided in the kit booklet without any modifications to the procedure. If there are still doubts about the results using the standard sample in the kit then send example results in the MegaCalc spread sheet to your product supplier (Megazyme or your local Megazyme distributor).

Q9. Can oligosaccharides or polysaccharides be measured using the kit assay?

The kit assay will only measure the non-covalently linked monosaccharide.

Oligosaccharides or polysaccharides can be measured after hydrolysis to the monosaccharide. Generally acid hydrolysis can be achieved by boiling the oligo/polysaccharide in 1.3 M HCl for 1 h. It is recommended that scientific literature is consulted for information on hydrolysis conditions for the particular oligo/polysaccharide that is being measured.

Q10. Can the test kit be used to measure biological fluids and what sample preparation method should be used?

The kit assay may work for biological fluids assuming that inositol is present above the limit of detection for the kit after any sample preparation (if required). Centrifugation of the samples and use of the supernatant directly in the kit assay (with appropriate dilution in distilled water) may be sufficient. However, if required a more stringent sample preparation method may be required and examples are provided at the following link:http://www.megazyme.com/docs/analytical-applications-downloads/biological_samples_111109.pdf?sfvrsn=2

The test kit has not been tested using biological fluids as samples because it is not marketed or registered as a medical device. This will therefore require your own validation.

Q11. Can the sensitivity of the kit assay be increased?

For samples with low concentrations of analyte the sample volume used in the kit assay can be increased to increase sensitivity. When doing this the water volume is adjusted to retain the same final assay volume. This is critical for the manual assay format because the assay volume and sample volume are used in the calculation of results.

Q12. How much sample should be used for the clarification/extraction of my sample?

The volume/weight of sample and total volume of the extract can be modified to suit the sample. This will ultimately be dictated by the amount of analyte of interest in the sample and may require empirical determination. For low levels of analyte the sample:extract volume ratio can be increased (i.e. increase the sample and/or decrease the total extraction volume).

Alternatively, for samples with low concentrations of analyte, a larger sample volume can be added to the kit assay. When altering the sample volume adjust the distilled water volume added to the assay accordingly so that the total assay volume is not altered.

Q13. Can the manual assay format be scaled down to a 96-well microplate format?

The majority of the Megazyme test kits are developed to work in cuvettes using the manual assay format, however the assay can be converted for use in a 96-well microplate format. To do this the assay volumes for the manual cuvette format are reduced by 10-fold. The calculation of results for the manual assay format uses a 1 cm path-length, however the path-length in the microplate is not 1 cm and therefore the MegaCalc spreadsheet or the calculation provided in the kit booklet for the manual format cannot be used for the micropalate format unless the microplate reader being used can.

There a 3 main methods for calculation of results using the microplate format:

  1. The easiest method is to use a microplate reader that has a path-length conversion capability (i.e. the microplater reader can detect the path-length of each well and convert the individual readings to a 1 cm path-length). This will allow values to be calculated using the MegaCalc calculation software which can be found where the product is located on the Megazyme website.
  2. Perform a standard curve of the analyte on each microplate that contains test samples and calculate the result of the test samples from the calibration curve (concentration of analyte versus absorbance).
  3. Perform a standard curve of the analyte in both the cuvette format (i.e. with a 1 cm path-length) and the 96-well microplate format and use these results to obtain a mean conversion factor between the cuvette values and the microplate values. Subsequent assays in the microplate format can then be converted from the calculated conversion factor.

Q14. Is it possible to add a larger volume then 2 μL of enzyme to the microplate assay? In some instances 2 μL can be difficult to pipette manually.

Yes, instead of adding 2 μL of enzyme suspension an alternative is to dilute the enzyme and add a larger volume to the microplate assay.

Dilute the assay buffer 10-fold with distilled water and use this as the diluent to dilute an aliquot of the enzyme suspension also by 10-fold. Instead of 2 μL, use 20 μL of the diluted enzyme in the microplate assay.

Q15. When using this kit for quantitative analysis what level of accuracy and repeatability can be expected?

The test kit is extremely accurate – at Megazyme the quality control criteria for accuracy and repeatability is to be within 2% of the expected value using pure analytes.

However, the level of accuracy is obviously analyst and sample dependent.

Q16. Must the minimum absorbance change for a sample always be at least 0.1?

No. The 0.1 change of absorbance is only a recommendation. The lowest acceptable change in absorbance can is dictated by the analyst and equipment (i.e. pipettes and spectrophotometer) and therefore can be can be determined by the user. With accurate pipetting, absorbance changes as low as 0.02 can be used accurately.
If a change in absorbance above 0.1 is required but cannot be achieved due to low concentrations of analyte in a sample, this can be overcome by using a larger sample volume in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results. 

Q17. Can the sensitivity of the kit assay be increased?

Yes. Samples with the lower concentrations of analyte will generate a lower absorbance change. For samples with low concentrations of analyte, a larger sample volume can be used in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results.

Megazyme D-果糖D-葡萄糖检测试剂盒操作视频（K-FRUGL）

Megazyme 溶解淀粉 操作视频

Megazyme 试剂盒样品前处理准备操作视频

葡萄糖氧化酶/催化酶混合物 Glucose oxidase – Catalase Mixture (eukaryote) 货号：E-GOXCA Megazyme试剂盒

发表于由
葡萄糖氧化酶/催化酶混合物

英文名：Glucose oxidase – Catalase Mixture (eukaryote)

货号：E-GOXCA

规格：2 vials – 200 tests

市场价： 1900元

High purity Glucose oxidase/Catalase Mixture (eukaryote) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
For use in removal of excess glucose in conjunction with the Sucrose/Glucose Assay Kit (K-SUCGL) and the Fructan HK Assay Kit (K-FRUCHK). Sufficient reagent for 200 incubations.

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葡萄糖6磷酸脱氢酶[肠膜明串珠菌] Glucose 6-phosphate dehydrogenase (Leuconostoc mesenteroides) 货号：E-GPDH5 Megazyme试剂盒

发表于由
葡萄糖6磷酸脱氢酶[肠膜明串珠菌]

英文名：Glucose 6-phosphate dehydrogenase (Leuconostoc mesenteroides)

货号：E-GPDH5

规格：5000 Units

市场价： 2900元

High purity Glucose 6-phosphate dehydrogenase (L. mesenteroides) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.

EC 1.1.1.49

From Leuconostoc mesenteroides. 
In 3.2 M ammonium sulphate.

Specific activity: > 800 U/mg (30oC, pH 7.8, glucose-6-phosphate).

Stable at 4oC for > 4 years.

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D-果糖/D-葡萄糖[液体即用型]检测试剂盒 D-Fructose /D-Glucose (Liquid Ready Reagent) Assay Kit 货号：K-FRGLQR Megazyme试剂盒

发表于由
D-果糖/D-葡萄糖[液体即用型]检测试剂盒

英文名：D-Fructose /D-Glucose (Liquid Ready Reagent) Assay Kit

货号：K-FRGLQR

规格：1100 assays per kit in autoanalyser format

市场价： 2862元

The D-Fructose/D-Glucose (Liquid Ready Reagents) test kit is a rapid, reliable and accurate method for the specific measurement and analysis of D-fructose and D-glucose in wine, beverages, foodstuffs and other materials. Supplied as a "ready to use" liquid stable formulation that is suitable for auto-analyser and microplate formats.
Suitable for auto-analyser and microplate formats.

UV-method suitable for auto-analyser and microplate formats for
the determination of D-Fructose and D-Glucose in foodstuffs,
beverages and other materials

Principle:
(hexokinase)
(1) D-Glucose + ATP → G-6-P + ADP

(hexokinase)
(2) D-Fructose + ATP → F-6-P + ADP

(glucose-6-phosphate dehydrogenase)
(3) G-6-P + NADP+ → gluconate-6-phosphate + NADPH + H+

(phosphoglucose isomerase)
(4) F-6-P ↔ G-6-P

Kit size:                           1100 assays (microplate) / 1100 (auto-analyser)
Method:                           Spectrophotometric at 340 nm
Reaction time:                 ~ 13 min
Detection limit:                133 mg/L (recommended format)
Application examples:
Wine, beer, fruit juices, soft drinks, milk, jam, honey, dietetic foods,
bread, bakery products, candies, desserts, confectionery, ice-cream,
fruit and vegetables, condiments, tobacco, cosmetics, pharmaceuticals,
paper and other materials (e.g. biological cultures, samples, etc.)
Method recognition:     
Methods based on this principle have been accepted by AOAC, EN,
NEN, NF, DIN, GOST, OIV, IFU, AIJN, MEBAK and IOCCC

Advantages

  • PVP incorporated to prevent tannin inhibition
  • “Ready to use” liquid stable formulation
  • Very competitive price (cost per test)
  • All reagents stable for > 2 years
  • Very rapid reaction (~ 13 min)
  • Standard included
  • Suitable for microplate and auto-analyser formats

 Q1. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample,  in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q2. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q3. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q4. The pH of my sample is low (pH ~ 3.0), do I need to adjust this before I use the sample in the kit assay?

The final pH of the kit assay after the sample is added should not change from what it should be (as stated in the kit for the assay buffer). If it does change then the sample will require pH adjustment. In most cases the sample volume being used is low relative to the final assay volume and in this case the pH of the kit assay is unlikely to be affected.

Q5. How can I work out how much sample to extract and what dilution of my sample should be used in the kit assay?

Where the amount of analyte in a liquid sample is unknown, it is recommended that a range of sample dilutions are prepared with the aim of obtaining an absorbance change in the assay that is within the linear range.
Where solid samples are analysed, the weight of sample per volume of water used for sample extraction/preparation can be altered to suit, as can the dilution of the extracted sample prior to the addition of the assay, as per liquid samples.

Q6. Can you explain, step by step, how to follow the method and perform the kit assay?

For users who are not familiar with how to use the Megazyme tests kits then it is recommended that they follow this example, e.g. D-Fructose/D-Glucose Assay kit K-FRUGL (http://secure.megazyme.com/D-Fructose-D-Glucose-Assay-Kit):

1. The kit components are listed on pages 2-3 of the kit booklet.
2. Prepare the kit reagents as described on page 3.
3. For separate measurements of glucose and fructose follow procedure A on page 4.
4. Pipette the volumes listed for water, sample, solution 1 and solution 2 into 3 mL, 1 cm pathlength cuvettes. Duplicate sample assays and duplicate blanks are recommended. Mix the contents of each cuvette by inversion (seal the cuvette using parafilm or a plastic cuvette cap – do not use a finger) then after ~3 min record the first absorbance reading of each cuvette at 340 nm (this is reading A1).
5. Then add suspension 3 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then record the absorbance reading of each cuvette at 340 nm (this is reading A2). NB. It is essential that the reaction is compete. To assess this, record the absorbances at ~ 2 minute intervals and until the absorbance plateaus. A stable absorbance indicates that the reaction is complete. If the absorbance continues to increase then continue to record absorbances until it plateaus and only then record absorbance reading A2.
6. Then add suspension 4 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then take absorbance reading of each cuvette at 340 nm (this is reading A3). NB. As above, assess that the reaction has completed by take subsequent readings at ~2 min intervals.
7. For simple, automated results analysis, input the absorbance readings (A1, A2, A3) for samples and blanks into the K-FRUGL MegaCalc.

To ensure that the assay is working, and being performed correctly it is recommend that the test is performed using the standard sample that is provided with the kit and to obtain the expected values before proceeding to test real samples.
It is recommend that new users also watch this video which highlights how to perform the assays.
Many of the other Megazyme test kits follow a similar format.

Q7. I have some doubts about the appearance/quality of a kit component what should be done?

If there are any concerns with any kit components, the first thing to do is to test the standard sample (control sample) that is supplied with the kit and ensure that the expected value (within the accepted variation) is obtained before testing any precious samples. This must be done using the procedure provided in the kit booklet without any modifications to the procedure. If there are still doubts about the results using the standard sample in the kit then send example results in the MegaCalc spread sheet to your product supplier (Megazyme or your local Megazyme distributor).

Q8. Can oligosaccharides or polysaccharides be measured using the kit assay?

The kit assay will only measure the non-covalently linked monosaccharide.

Oligosaccharides or polysaccharides can be measured after hydrolysis to the monosaccharide. Generally acid hydrolysis can be achieved by boiling the oligo/polysaccharide in 1.3 M HCl for 1 h. It is recommended that scientific literature is consulted for information on hydrolysis conditions for the particular oligo/polysaccharide that is being measured.

Q9. Can the sensitivity of the kit assay be increased?

For samples with low concentrations of analyte the sample volume used in the kit assay can be increased to increase sensitivity. When doing this the water volume is adjusted to retain the same final assay volume. This is critical for the manual assay format because the assay volume and sample volume are used in the calculation of results.

Q10. Can the test kit be used to measure biological fluids and what sample preparation method should be used?

The kit assay may work for biological fluids assuming that inositol is present above the limit of detection for the kit after any sample preparation (if required). Centrifugation of the samples and use of the supernatant directly in the kit assay (with appropriate dilution in distilled water) may be sufficient. However, if required a more stringent sample preparation method may be required and examples are provided at the following link:http://www.megazyme.com/docs/analytical-applications-downloads/biological_samples_111109.pdf?sfvrsn=2

The test kit has not been tested using biological fluids as samples because it is not marketed or registered as a medical device. This will therefore require your own validation.

Q11. Can the manual assay format be scaled down to a 96-well microplate format?

The majority of the Megazyme test kits are developed to work in cuvettes using the manual assay format, however the assay can be converted for use in a 96-well microplate format. To do this the assay volumes for the manual cuvette format are reduced by 10-fold. The calculation of results for the manual assay format uses a 1 cm path-length, however the path-length in the microplate is not 1 cm and therefore the MegaCalc spreadsheet or the calculation provided in the kit booklet for the manual format cannot be used for the micropalate format unless the microplate reader being used can.

There a 3 main methods for calculation of results using the microplate format:

  1. The easiest method is to use a microplate reader that has a path-length conversion capability (i.e. the microplater reader can detect the path-length of each well and convert the individual readings to a 1 cm path-length). This will allow values to be calculated using the MegaCalc calculation software which can be found where the product is located on the Megazyme website.
  2. Perform a standard curve of the analyte on each microplate that contains test samples and calculate the result of the test samples from the calibration curve (concentration of analyte versus absorbance).
  3. Perform a standard curve of the analyte in both the cuvette format (i.e. with a 1 cm path-length) and the 96-well microplate format and use these results to obtain a mean conversion factor between the cuvette values and the microplate values. Subsequent assays in the microplate format can then be converted from the calculated conversion factor.

Q12. How much sample should be used for the clarification/extraction of my sample?

The volume/weight of sample and total volume of the extract can be modified to suit the sample. This will ultimately be dictated by the amount of analyte of interest in the sample and may require empirical determination. For low levels of analyte the sample:extract volume ratio can be increased (i.e. increase the sample and/or decrease the total extraction volume).

Alternatively, for samples with low concentrations of analyte, a larger sample volume can be added to the kit assay. When altering the sample volume adjust the distilled water volume added to the assay accordingly so that the total assay volume is not altered.

Q13. Is it possible to add a larger volume then 2 μL of enzyme to the microplate assay? In some instances 2 μL can be difficult to pipette manually.

Yes, instead of adding 2 μL of enzyme suspension an alternative is to dilute the enzyme and add a larger volume to the microplate assay.

Dilute the assay buffer 10-fold with distilled water and use this as the diluent to dilute an aliquot of the enzyme suspension also by 10-fold. Instead of 2 μL, use 20 μL of the diluted enzyme in the microplate assay.

Q14. When using this kit for quantitative analysis what level of accuracy and repeatability can be expected?

The test kit is extremely accurate – at Megazyme the quality control criteria for accuracy and repeatability is to be within 2% of the expected value using pure analytes.

However, the level of accuracy is obviously analyst and sample dependent.

Q15. Must the minimum absorbance change for a sample always be at least 0.1?

No. The 0.1 change of absorbance is only a recommendation. The lowest acceptable change in absorbance can is dictated by the analyst and equipment (i.e. pipettes and spectrophotometer) and therefore can be can be determined by the user. With accurate pipetting, absorbance changes as low as 0.02 can be used accurately.
If a change in absorbance above 0.1 is required but cannot be achieved due to low concentrations of analyte in a sample, this can be overcome by using a larger sample volume in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results. 

Q16. Can the sensitivity of the kit assay be increased?

Yes. Samples with the lower concentrations of analyte will generate a lower absorbance change. For samples with low concentrations of analyte, a larger sample volume can be used in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results.

D-葡萄糖[GOPOD法]检测试剂盒 D-Glucose (GOPOD Format) Assay Kit 货号：K-GLUC Megazyme试剂盒

发表于由
D-葡萄糖[GOPOD法]检测试剂盒

英文名：D-Glucose (GOPOD Format) Assay Kit

货号：K-GLUC

规格：660 assays per kit

市场价： 3710元

 分析物意义：常见食品组分，在某些情况下非常重要，如糖尿病产品   D-葡萄糖[GOPOD法]检测试剂盒 D-Glucose (GOPOD Format) Assay Kit 货号：K-GLUC Megazyme试剂盒

Megazyme检测试剂盒优点：选择简单可用的方法，葡萄糖氧化酶/过氧化酶 /己糖激酶/6-磷酸葡萄糖脱氢酶。试剂稳定

D-葡萄糖[GOPOD法]检测试剂盒 D-Glucose (GOPOD Format) Assay Kit 货号：K-GLUC Megazyme试剂盒

The D-Glucose test kit contains high purity reagents for the measurement and analysis of D-glucose in cereal extracts and for use in combination with other Megazyme kits.

Colourimetric method for the determination of D-Glucose in
foodstuffs, beverages and other materials

Principle:
(glucose oxidase)
(1) D-Glucose + H2O + O2 → D-gluconate + H2O2

(peroxidase)
(2) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine →
quinoneimine + 4H2O

Kit size:                             660 assays 
Method:                             Spectrophotometric at 510 nm
Reaction time:                   ~ 20 min
Detection limit:                  100 mg/L
Application examples: 
Wine, beer, fruit juices, soft drinks, milk, jam, dietetic foods, bakery
products, candies, fruit and vegetables, tobacco, cosmetics, pharmaceuticals,
feed, paper and other materials (e.g. biological cultures, samples, etc.)
Method recognition:     
Widely used and accepted in clinical chemistry and food analysis

Advantages

  • All reagents stable for > 12 months after preparation
  • Very competitive price (cost per test)
  • Simple format
  • Standard included

 Q1. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q2. I have some questions regarding the Glucose Oxidase and peroxidase in the Glucose Assay Kit. At what optimal pH do the enzymes work? Does the sample that is added to the enzyme mix show incorrect results if it is outside a certain pH range?

The test is best run at pH 7.4.  The reagent is buffered at this pH.  Using different pH values will affect results, i.e. it may take longer to reach this end point; but the same end-point value should be obtained if not too far away from this pH value.

Q3. What is the linear range of the Glucose Assay Kit?

The test is set up to measure between 10 and 100 micrograms per assay (i.e. 0.1 mL of 0.1 to 1.0 mg/mL).  You may prefer to use 3.0 mL of GOPOD reagent mixture plus 1.0 mL of sample; in this case the concentration range in the material being analysed (diluted) should be ~10 to 100 micrograms per mL.  The test is linear up to an absorbance of 1.4 (final assay volume of 3.2 mL).  If the final volume is 4.0 mL, then linearity will be up to about 1.0 absorbance units.

Q4. I have some questions on your Glucose Assay Kit. Is the colour stable at room temperature? Does the reaction continue if not read within 20 minutes?

The reaction is complete after approx. 15 min, and the colour is stable at temperatures of 20-50˚C for at least an extra hour.

Q5. Please let us know the lower limit of detection of measuring glucose using your Glucose Assay Kit (mg/mL).

1 microgram gives an absorbance of 0.01 if 3 mL of GOPOD are used.  If 1 mL of GOPOD is used, 1 microgram gives an absorbance of 0.03 OD. 

Q6. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q7. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q8. We stored the Glucose Assay Kit at 0-5°C for some weeks, because that is what is written on the package. Now we have noticed on some of the vials it says storage at –20°C. Can you tell me how long the products can be stored at 0-5°C without damage?

The kit enzymes can be stored at 0-5°C for up to 12 months, so they will be perfectly fine.

Q9. The temperature for the Glucose Assay Procedure (40 or 50˚C)-is this for incubation of the mix or reading the results at the spectrophotometer? Could I read the results at room temperature?

The temperature is just for the incubations.  It is an end-point assay, so the spectrophotometer does not need to be temperature controlled.

Q10. Can oligosaccharides or polysaccharides be measured using the kit assay?

The kit assay will only measure the non-covalently linked monosaccharide.

Oligosaccharides or polysaccharides can be measured after hydrolysis to the monosaccharide. Generally acid hydrolysis can be achieved by boiling the oligo/polysaccharide in 1.3 M HCl for 1 h. It is recommended that scientific literature is consulted for information on hydrolysis conditions for the particular oligo/polysaccharide that is being measured.

己糖激酶/葡萄糖-6-磷酸脱氢酶 Hexokinase/Glucose-6-phosphate dehydrogenase 货号：E-HKGDH Megazyme试剂盒

发表于由
己糖激酶/葡萄糖-6-磷酸脱氢酶

英文名：Hexokinase/Glucose-6-phosphate dehydrogenase

货号：E-HKGDH

规格：10ml

市场价： 2756元

High purity Hexokinase (420 U/ml) + G6P-DH (210 U/ml) for use in research, biochemical enzyme assays and in vitrodiagnostic analysis.  

EC 2.7.1.1 and EC 1.1.1.49.

From yeast and Leuconostoc mesenteroides, respectively.
In 3.2 M ammonium sulphate.

Activity: Hexokinase > 420 U/mL (25oC, pH 7.4, glucose); glucose-6-phosphate dehydrogenase > 210 U/mL (25oC, 
pH 7.4, glucose-6-phosphate). 
For use in determination of D-glucose.

Stable at 4oC for > 4 years.

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D-葡萄糖[HK法]检测试剂盒 D-Glucose HK Assay Kit 货号：K-GLUHK-110A Megazyme试剂盒

发表于由
D-葡萄糖[HK法]检测试剂盒

英文名：D-Glucose HK Assay Kit

货号：K-GLUHK-110A

规格：110 assays (manual) / 1100 (microplate) / 1000 (auto-analyser)

市场价： 2862元

分析物意义：常见食品组分，在某些情况下非常重要，如糖尿病产品   

Megazyme检测试剂盒优点：选择简单可用的方法，葡萄糖氧化酶/过氧化酶 /己糖激酶/6-磷酸葡萄糖脱氢酶。试剂稳定

High purity reagents for the assay of D-glucose in plant and food products. Can be used in combination with other Megazyme products that require glucose determination. Content:110 assays per kit

UV-method for the determination of D-Glucose in foodstuffs,
beverages and other materials

Principle:
(hexokinase)
(1) D-Glucose + ATP → G-6-P + ADP

(glucose-6-phosphate dehydrogenase)
(2) G-6-P + NADP+ → gluconate-6-phosphate + NADPH + H+

Kit size:                              (K-GLUHKR)
                                          110 assays (manual) / 1100 (microplate) 
                                           / 1000 (auto-analyser) or
                                          (K-GLUHKL)
                                          220 assays (manual)  / 2200 (microplate) 
                                           / 2000 (auto-analyser)
Method:                              Spectrophotometric at 340 nm
Reaction time:                    ~ 5 min
Detection limit:                   0.66 mg/L
Application examples: 
Wine, beer, fruit juices, soft drinks, milk, jam, dietetic foods, bakery
products, candies, fruit and vegetables, tobacco, cosmetics, pharmaceuticals
(e.g. infusions), feed, paper (and cardboard) and other materials (e.g.
biological cultures, samples, etc.)
Method recognition:     
Methods based on this principle have been accepted by AOAC, EN,
NEN, NF, DIN, GOST, OIV, IFU, AIJN and MEBAK

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 2 years after preparation
  • Rapid reaction
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included
  • Extended cofactors stability
  • Suitable for manual, microplate and auto-analyser formats

 Q1. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q2. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q3. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q4. Is it possible to detect glucose when it is bound via a glycosidic linkage?

No.  The K-GLUHKL test kit is specific for the measurement of “free” D-glucose.  It will not detect glucose that is bound by a glycosidic linkage to another sugar molecule. 

Q5. Can K-GLUHKL be used to measure glucose in biological samples?

Yes.  It is possible that biological samples may be used directly after appropriate sample dilution in distilled water, however some biological samples may require deproteinisation with perchloric acid prior to addition to the assay.  The deproteinisation method can be found at the following link on the Megazyme website: Deproteinisation Method

Dilution during sample preparation must be taken into account in the final calculation.

Q6. Can K-GLUHKL be used to measure glucose as a component of polysaccharides in plant material?

Yes.  Determination of D-glucose in polysaccharides and fibrous plant material: 
Mill plant material or polysaccharide to pass a 0.5 mm screen using a Retsch centrifugal mill, or similar.  Accurately weigh approx. 100 mg of material into a Corning screw-cap culture tube (16 x 125 mm).  Add 5 mL of 1.3 M HCl to each tube and cap the tubes.  Incubate the tubes at 100˚C for 1 h.  Stir the tubes intermittently during the incubation.  Cool the tubes to room temperature, carefully loosen the caps and add 5 mL of 1.3 M NaOH.  Quantitatively transfer the contents of the tube to a 100 mL volumetric flask using distilled water and adjust the volume to 100 mL with distilled water.  Mix thoroughly by inversion and filter an aliquot of the solution through Whatman No. 1 filter paper or centrifuge at 1,500 g for 10 min.  Typically, no further dilution is required and a sample volume of 0.1 mL is satisfactory. 

Q7. Can oligosaccharides or polysaccharides be measured using the kit assay?

The kit assay will only measure the non-covalently linked monosaccharide.

Oligosaccharides or polysaccharides can be measured after hydrolysis to the monosaccharide. Generally acid hydrolysis can be achieved by boiling the oligo/polysaccharide in 1.3 M HCl for 1 h. It is recommended that scientific literature is consulted for information on hydrolysis conditions for the particular oligo/polysaccharide that is being measured.

Q8. Is it possible to add a larger volume then 2 μL of enzyme to the microplate assay? In some instances 2 μL can be difficult to pipette manually.

Yes, instead of adding 2 μL of enzyme suspension an alternative is to dilute the enzyme and add a larger volume to the microplate assay.

Dilute the assay buffer 10-fold with distilled water and use this as the diluent to dilute an aliquot of the enzyme suspension also by 10-fold. Instead of 2 μL, use 20 μL of the diluted enzyme in the microplate assay.

D-葡萄糖[HK法]检测试剂盒 D-Glucose HK Assay Kit 货号：K-GLUHK-220A Megazyme试剂盒

发表于由
D-葡萄糖[HK法]检测试剂盒

英文名：D-Glucose HK Assay Kit

货号：K-GLUHK-220A

规格：220 assays (manual) / 2200 (microplate) / 2000 (auto-analyser)

市场价： 4982元

分析物意义：常见食品组分，在某些情况下非常重要，如糖尿病产品   

Megazyme检测试剂盒优点：选择简单可用的方法，葡萄糖氧化酶/过氧化酶 /己糖激酶/6-磷酸葡萄糖脱氢酶。试剂稳定

High purity reagents for the assay of D-glucose in plant and food products. Can be used in combination with other Megazyme products that require glucose determination. Content:110 assays per kit

UV-method for the determination of D-Glucose in foodstuffs,
beverages and other materials

Principle:
(hexokinase)
(1) D-Glucose + ATP → G-6-P + ADP

(glucose-6-phosphate dehydrogenase)
(2) G-6-P + NADP+ → gluconate-6-phosphate + NADPH + H+

Kit size:                              (K-GLUHKR)
                                          110 assays (manual) / 1100 (microplate) 
                                           / 1000 (auto-analyser) or
                                          (K-GLUHKL)
                                          220 assays (manual)  / 2200 (microplate) 
                                           / 2000 (auto-analyser)
Method:                              Spectrophotometric at 340 nm
Reaction time:                    ~ 5 min
Detection limit:                   0.66 mg/L
Application examples: 
Wine, beer, fruit juices, soft drinks, milk, jam, dietetic foods, bakery
products, candies, fruit and vegetables, tobacco, cosmetics, pharmaceuticals
(e.g. infusions), feed, paper (and cardboard) and other materials (e.g.
biological cultures, samples, etc.)
Method recognition:     
Methods based on this principle have been accepted by AOAC, EN,
NEN, NF, DIN, GOST, OIV, IFU, AIJN and MEBAK

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 2 years after preparation
  • Rapid reaction
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included
  • Extended cofactors stability
  • Suitable for manual, microplate and auto-analyser formats

 Q1. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q2. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q3. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q4. Is it possible to detect glucose when it is bound via a glycosidic linkage?

No.  The K-GLUHKL test kit is specific for the measurement of “free” D-glucose.  It will not detect glucose that is bound by a glycosidic linkage to another sugar molecule. 

Q5. Can K-GLUHKL be used to measure glucose in biological samples?

Yes.  It is possible that biological samples may be used directly after appropriate sample dilution in distilled water, however some biological samples may require deproteinisation with perchloric acid prior to addition to the assay.  The deproteinisation method can be found at the following link on the Megazyme website: Deproteinisation Method

Dilution during sample preparation must be taken into account in the final calculation.

Q6. Can K-GLUHKL be used to measure glucose as a component of polysaccharides in plant material?

Yes.  Determination of D-glucose in polysaccharides and fibrous plant material: 
Mill plant material or polysaccharide to pass a 0.5 mm screen using a Retsch centrifugal mill, or similar.  Accurately weigh approx. 100 mg of material into a Corning screw-cap culture tube (16 x 125 mm).  Add 5 mL of 1.3 M HCl to each tube and cap the tubes.  Incubate the tubes at 100˚C for 1 h.  Stir the tubes intermittently during the incubation.  Cool the tubes to room temperature, carefully loosen the caps and add 5 mL of 1.3 M NaOH.  Quantitatively transfer the contents of the tube to a 100 mL volumetric flask using distilled water and adjust the volume to 100 mL with distilled water.  Mix thoroughly by inversion and filter an aliquot of the solution through Whatman No. 1 filter paper or centrifuge at 1,500 g for 10 min.  Typically, no further dilution is required and a sample volume of 0.1 mL is satisfactory. 

Q7. Can oligosaccharides or polysaccharides be measured using the kit assay?

The kit assay will only measure the non-covalently linked monosaccharide.

Oligosaccharides or polysaccharides can be measured after hydrolysis to the monosaccharide. Generally acid hydrolysis can be achieved by boiling the oligo/polysaccharide in 1.3 M HCl for 1 h. It is recommended that scientific literature is consulted for information on hydrolysis conditions for the particular oligo/polysaccharide that is being measured.

Q8. Is it possible to add a larger volume then 2 μL of enzyme to the microplate assay? In some instances 2 μL can be difficult to pipette manually.

Yes, instead of adding 2 μL of enzyme suspension an alternative is to dilute the enzyme and add a larger volume to the microplate assay.

Dilute the assay buffer 10-fold with distilled water and use this as the diluent to dilute an aliquot of the enzyme suspension also by 10-fold. Instead of 2 μL, use 20 μL of the diluted enzyme in the microplate assay.

D-甘露糖/D-果糖/D-葡萄糖检测试剂盒 D-Mannose/D-Fructose/D-Glucose Assay kit 货号：K-MANGL Megazyme试剂盒

发表于由
D-甘露糖/D-果糖/D-葡萄糖检测试剂盒

英文名：D-Mannose/D-Fructose/D-Glucose Assay kit

货号：K-MANGL

规格：55 assays per kit

市场价： 3922元

The D-Mannose/D-Fructose/D-Glucose test kit is suitable for the specific measurement and analysis of D-mannose, D-fructose and D-glucose in plant products and in acid hydrolysates of polysaccharides.

UV-method for the determination of D-Mannose, D-Fructose
and D-Glucosein foodstuffs, yeast cell preparations and
other materials

Principle:
(hexokinase)
(1) D-Mannose / D-fructose / D-glucose + ATP →
M-6-P / F-6-P / G-6-P + ADP

(glucose-6-phosphate dehydrogenase)
(2) G-6-P + NADP+ → gluconate-6-phosphate + NADPH + H+

(phosphomannose isomerase) (phosphoglucose isomerase)
(3) M-6-P ↔ F-6-P ↔ G-6-P

Kit size:                            55 assays
Method:                            Spectrophotometric at 340 nm
Reaction time:                  ~ 30 min
Detection limit:                 0.7 mg/L
Application examples: 
Foodstuffs, yeast cell preparations, enzymatic hydrolysates and other
materials (e.g. biological cultures, samples, etc.)
Method recognition:          Novel method

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 2 years after preparation
  • Only enzymatic kit available
  • Simple format
  • Rapid reaction
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included

 Q1. Sometimes a negative absorbance change is obtained for the blank samples, is this normal? Should the real value (negative absorbance change) or “0” be used in the calculation of results?

Sometimes the addition of the last assay component can cause a small negative absorbance change in the blank samples due to a dilution effect and in such cases it is recommended that the real absorbance values be used in the calculation of results.

Q2. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q3. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q4. How can I work out how much sample to extract and what dilution of my sample should be used in the kit assay?

Where the amount of analyte in a liquid sample is unknown, it is recommended that a range of sample dilutions are prepared with the aim of obtaining an absorbance change in the assay that is within the linear range.
Where solid samples are analysed, the weight of sample per volume of water used for sample extraction/preparation can be altered to suit, as can the dilution of the extracted sample prior to the addition of the assay, as per liquid samples.

Q5. Can the sensitivity of the kit assay be increased?

For samples with low concentrations of analyte the sample volume used in the kit assay can be increased to increase sensitivity. When doing this the water volume is adjusted to retain the same final assay volume. This is critical for the manual assay format because the assay volume and sample volume are used in the calculation of results.

Q6. I have some doubts about the appearance/quality of a kit component what should be done?

If there are any concerns with any kit components, the first thing to do is to test the standard sample (control sample) that is supplied with the kit and ensure that the expected value (within the accepted variation) is obtained before testing any precious samples. This must be done using the procedure provided in the kit booklet without any modifications to the procedure. If there are still doubts about the results using the standard sample in the kit then send example results in the MegaCalc spread sheet to your product supplier (Megazyme or your local Megazyme distributor).

Q7. How much sample should be used for the clarification/extraction of my sample?

The volume/weight of sample and total volume of the extract can be modified to suit the sample. This will ultimately be dictated by the amount of analyte of interest in the sample and may require empirical determination. For low levels of analyte the sample:extract volume ratio can be increased (i.e. increase the sample and/or decrease the total extraction volume).

Alternatively, for samples with low concentrations of analyte, a larger sample volume can be added to the kit assay. When altering the sample volume adjust the distilled water volume added to the assay accordingly so that the total assay volume is not altered.

Q8. Can the manual assay format be scaled down to a 96-well microplate format?

The majority of the Megazyme test kits are developed to work in cuvettes using the manual assay format, however the assay can be converted for use in a 96-well microplate format. To do this the assay volumes for the manual cuvette format are reduced by 10-fold. The calculation of results for the manual assay format uses a 1 cm path-length, however the path-length in the microplate is not 1 cm and therefore the MegaCalc spreadsheet or the calculation provided in the kit booklet for the manual format cannot be used for the micropalate format unless the microplate reader being used can.

There a 3 main methods for calculation of results using the microplate format:

  1. The easiest method is to use a microplate reader that has a path-length conversion capability (i.e. the microplater reader can detect the path-length of each well and convert the individual readings to a 1 cm path-length). This will allow values to be calculated using the MegaCalc calculation software which can be found where the product is located on the Megazyme website.
  2. Perform a standard curve of the analyte on each microplate that contains test samples and calculate the result of the test samples from the calibration curve (concentration of analyte versus absorbance).
  3. Perform a standard curve of the analyte in both the cuvette format (i.e. with a 1 cm path-length) and the 96-well microplate format and use these results to obtain a mean conversion factor between the cuvette values and the microplate values. Subsequent assays in the microplate format can then be converted from the calculated conversion factor.

Q9. Can the test kit be used to measure biological fluids and what sample preparation method should be used?

The kit assay may work for biological fluids assuming that inositol is present above the limit of detection for the kit after any sample preparation (if required). Centrifugation of the samples and use of the supernatant directly in the kit assay (with appropriate dilution in distilled water) may be sufficient. However, if required a more stringent sample preparation method may be required and examples are provided at the following link:http://www.megazyme.com/docs/analytical-applications-downloads/biological_samples_111109.pdf?sfvrsn=2

The test kit has not been tested using biological fluids as samples because it is not marketed or registered as a medical device. This will therefore require your own validation.

Q10. When using this kit for quantitative analysis what level of accuracy and repeatability can be expected?

The test kit is extremely accurate – at Megazyme the quality control criteria for accuracy and repeatability is to be within 2% of the expected value using pure analytes.

However, the level of accuracy is obviously analyst and sample dependent.

Q11. Must the minimum absorbance change for a sample always be at least 0.1?

No. The 0.1 change of absorbance is only a recommendation. The lowest acceptable change in absorbance can is dictated by the analyst and equipment (i.e. pipettes and spectrophotometer) and therefore can be can be determined by the user. With accurate pipetting, absorbance changes as low as 0.02 can be used accurately.
If a change in absorbance above 0.1 is required but cannot be achieved due to low concentrations of analyte in a sample, this can be overcome by using a larger sample volume in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results. 

Q12. Can the sensitivity of the kit assay be increased?

Yes. Samples with the lower concentrations of analyte will generate a lower absorbance change. For samples with low concentrations of analyte, a larger sample volume can be used in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results.

Q13. Must the minimum absorbance change for a sample always be at least 0.1?

No. The 0.1 change of absorbance is only a recommendation. The lowest acceptable change in absorbance can is dictated by the analyst and equipment (i.e. pipettes and spectrophotometer) and therefore can be can be determined by the user. With accurate pipetting, absorbance changes as low as 0.02 can be used accurately.
If a change in absorbance above 0.1 is required but cannot be achieved due to low concentrations of analyte in a sample, this can be overcome by using a larger sample volume in the assay to increase the absorbance change and thereby increase sensitivity of the assay. When doing this the increased volume of the sample should be subtracted from the distilled water volume that is added to the assay so that the total assay volume is unaltered. The increase sample volume should also be accounted for when calculating final results. 

密三糖或棉子糖/蔗糖/D-半乳糖检测试剂盒 Raffinose/Sucrose/D-Glucose Assay Kit 货号：K-RAFGL Megazyme试剂盒

发表于由
密三糖或棉子糖/蔗糖/D-半乳糖检测试剂盒

英文名：Raffinose/Sucrose/D-Glucose Assay Kit

货号：K-RAFGL

规格：120 assays of each per kit

市场价： 4982元

The Raffinose/Sucrose/D-Glucose test kit is for the measurement and analysis of D-glucose, sucrose and raffinose, stachyose and verbascose in seeds and seed meals. Based on the measurement of D-glucose on enzymic hydrolysis of raffinose, stachyose and verbascose to D-glucose, D-fructose and D-galactose.

Colourimetric method for the determination of Raffinose (also
stachyose and verbascose), Sucrose and D-Glucose in
legume seeds, plant materials, foodstuffs and feed

Principle:
(α-galactosidase)
(1) Raffinose + stachyose + verbascose + H2O → D-galactose +
sucrose

(invertase)
(2) Sucrose + H2O → D-glucose + D-fructose

(glucose oxidase)
(3) D-Glucose + H2O + O2 → D-gluconate + H2O2

(peroxidase)
(4) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine →
quinoneimine + 4H2O

Kit size:                           120 assays
Method:                           Spectrophotometric at 510 nm
Reaction time:                 ~ 20 min
Detection limit:                100 mg/L
Application examples: 
Analysis of grain legumes and other materials containing raffinose,
stachyose and verbascose
Method recognition:         Used and accepted in food analysis

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 2 years after preparation
  • Simple format
  • Rapid reaction
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included

 

 Q1. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q2. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

蔗糖/D-葡萄糖检测试剂盒 Sucrose/D-Glucose Assay Kit 货号：K-SUCGL Megazyme试剂盒

发表于由
蔗糖/D-葡萄糖检测试剂盒

英文名：Sucrose/D-Glucose Assay Kit

货号：K-SUCGL

规格：250 assays per kit

市场价： 4240元

分析物意义： 常见食品组分

 

Megazyme检测试剂盒优点： 选择简单可用的方法，葡萄糖氧化酶/过氧化酶/己糖激酶/6-磷酸葡萄糖脱氢酶。试剂稳定

The Sucrose/D-Glucose test kit is suitable for the measurement and analysis of sucrose and D-glucose in fruit juice, beverages, honey and food products.

Colourimetric method for the determination of Sucrose and
D-Glucose in foodstuffs, beverages and other materials

Principle:
(glucose oxidase)
(1) D-Glucose + H2O + O2 → D-gluconate + H2O2

(peroxidase)
(2) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine →
quinoneimine + 4H2O

(β-fructosidase)
(3) Sucrose + H2O → D-glucose + D-fructose

Kit size:                             250 assays
Method:                             Spectrophotometric at 510 nm
Reaction time:                   ~ 30 min
Detection limit:                  100 mg/L
Application examples: 
Beer, fruit juices, soft drinks, coffee, milk, jam, honey, dietetic foods,
bread, bakery products, candies, chocolate, desserts, confectionery,
ice-cream, fruit and vegetables, condiments, tobacco, cosmetics,
pharmaceuticals, paper and other materials (e.g. biological cultures,
samples, etc.)
Method recognition:     
Used and accepted in food analysis

Advantages

  • Very competitive price (cost per test)
  • All reagents stable for > 12 months after preparation
  • Simple format
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing
  • Standard included

 

 Q1. Should the pH of the sample be adjusted even for samples in acidic media?

The pH of the assay solution after the sample is added should be the same as that of the assay buffer that is supplied with the kit.
Low sample volumes (e.g. 0.1 mL) are not likely to affect the pH of the assay solution and therefore may not require pH adjustment.
Samples above 0.1 mL are more likely to affect the pH of the assay solution and therefore the pH of these samples should be adjusted as described in the data booklet, prior to addition to the assay.

Q2. There is an issue with the performance of the kit; the results are not as expected.

If you suspect that the Megazyme test kit is not performing as expected such that expected results are not obtained please do the following:

  1. Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
  2. Send the results of the kit standard, blank samples and the results obtained for your sample, in the relevant MegaCalc spreadsheet (if available) to Megazyme (cs@megazyme.com). Where available the relevant MegaCalc spreadsheet can be downloaded from where the product appears on the Megazyme website.
  3. State the kit lot number being used (this is found on the outside of the kit box).
  4. State which assay format was used (refer to the relevant page in the kit booklet if necessary).
  5. State exact details of any modifications to the standard procedure that is provided by Megazyme.
  6. State the sample type and describe the sample preparation steps if applicable.

Q3. How can I work out how much sample to extract and what dilution of my sample should be used in the kit assay?

Where the amount of analyte in a liquid sample is unknown, it is recommended that a range of sample dilutions are prepared with the aim of obtaining an absorbance change in the assay that is within the linear range.
Where solid samples are analysed, the weight of sample per volume of water used for sample extraction/preparation can be altered to suit, as can the dilution of the extracted sample prior to the addition of the assay, as per liquid samples.

Q4. The pH of my sample is low (pH ~ 3.0), do I need to adjust this before I use the sample in the kit assay?

The final pH of the kit assay after the sample is added should not change from what it should be (as stated in the kit for the assay buffer). If it does change then the sample will require pH adjustment. In most cases the sample volume being used is low relative to the final assay volume and in this case the pH of the kit assay is unlikely to be affected.

Q5. Can you explain, step by step, how to follow the method and perform the kit assay?

For users who are not familiar with how to use the Megazyme tests kits then it is recommended that they follow this example, e.g. D-Fructose/D-Glucose Assay kit K-FRUGL (http://secure.megazyme.com/D-Fructose-D-Glucose-Assay-Kit):

1. The kit components are listed on pages 2-3 of the kit booklet.
2. Prepare the kit reagents as described on page 3.
3. For separate measurements of glucose and fructose follow procedure A on page 4.
4. Pipette the volumes listed for water, sample, solution 1 and solution 2 into 3 mL, 1 cm pathlength cuvettes. Duplicate sample assays and duplicate blanks are recommended. Mix the contents of each cuvette by inversion (seal the cuvette using parafilm or a plastic cuvette cap – do not use a finger) then after ~3 min record the first absorbance reading of each cuvette at 340 nm (this is reading A1).
5. Then add suspension 3 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then record the absorbance reading of each cuvette at 340 nm (this is reading A2). NB. It is essential that the reaction is compete. To assess this, record the absorbances at ~ 2 minute intervals and until the absorbance plateaus. A stable absorbance indicates that the reaction is complete. If the absorbance continues to increase then continue to record absorbances until it plateaus and only then record absorbance reading A2.
6. Then add suspension 4 and mix the contents of each cuvette by inversion. Incubate for 5 minutes then take absorbance reading of each cuvette at 340 nm (this is reading A3). NB. As above, assess that the reaction has completed by take subsequent readings at ~2 min intervals.
7. For simple, automated results analysis, input the absorbance readings (A1, A2, A3) for samples and blanks into the K-FRUGL MegaCalc.

To ensure that the assay is working, and being performed correctly it is recommend that the test is performed using the standard sample that is provided with the kit and to obtain the expected values before proceeding to test real samples.
It is recommend that new users also watch this video which highlights how to perform the assays.
Many of the other Megazyme test kits follow a similar format.

葡萄糖-6-磷酸脱氢酶（大肠杆菌） Glucose 6-phosphate dehydrogenase (E. coli) 货号：E-GPDHEC Megazyme试剂盒

发表于由
葡萄糖-6-磷酸脱氢酶（大肠杆菌）

英文名：Glucose 6-phosphate dehydrogenase (E. coli)

货号：E-GPDHEC

规格：5000 Units

市场价： 2800元

High purity recombinant Glucose 6-phosphate dehydrogenase (E. Coli) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.

EC 1.1.1.49

Recombinant from E. coli. 
In 3.2 M ammonium sulphate.
Supplied at ~ 1,250 U/mL. 

Specific activity: 172 U/mg (25oC, pH 7.6, D-glucose-6-phosphate).

Stable at 4oC for > 2 years.

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Gibco™ DMEM, high glucose, HEPES代理商

发表于由

上海金畔生物科技有限公司是Gibco™ DMEM, high glucose, HEPES代理商 ，欢迎访问官网了解更多产品信息和订购。
Gibco™ DMEM, high glucose, HEPES

详情介绍

Gibco™ DMEM, high glucose, HEPES

Using DMEM：

DMEM is unique from other media as it contains 4 times the concentration of amino acids and vitamins than the original Eagle's Minimal Essential Medium. DMEM was originally formulated with low glucose (1 g/L) and sodium pyruvate, but is often used with higher glucose levels, with or without sodium pyruvate. DMEM contains no proteins, lipids, or growth factors. Therefore, DMEM requires supplementation, commonly with 10% Fetal Bovine Serum (FBS). DMEM uses a sodium bicarbonate buffer system (3.7 g/L), and therefore requires a 5–10% CO2 environment to maintain physiological pH.


cGMP manufacturing and quality system：

DMEM is manufactured at a cGMP-compliant facility located in Grand Island, New York. The facility is registered with the FDA as a medical device manufacturer and is certified to ISO 13485 standards. For supply chain continuity, we offer an identical DMEM product made in our Scotland facility (42430-082). This facility is registered with the FDA as a medical device manufacturer and is certified to the ISO 13485 standard.


Gibco高唐培养基DMEM 11995-065 500ml11995-065

发表于由

Gibco高唐培养基DMEM 11995-065 500ml

简要描述：
DMEM, High Glucose, Pyruvate
描述
含有 4500 mg/L D-葡萄糖、L-谷氨酰胺和 110 mg/L 丙酮酸钠。

Gibco高唐培养基DMEM 11995-065

DMEM, High Glucose, Pyruvate
描述：含有 4500 mg/L D-葡萄糖、L-谷氨酰胺和 110 mg/L 丙酮酸钠。

详细说明

常用规格

 

Form:

Liquid 
Volume:

500 ml 
Glucose:

High Glucose 
Glutamine:

L-Glutamine 
HEPES Buffer:

No HEPES 
Product Size:

500 ml 
Phenol Red Indicator:

Phenol Red 
Serum Supplementation:

Standard Serum Supplementation 
Sodium Pyruvate Additive:

Sodium Pyruvate 

内容和储存

Storage conditions: 2-8° C. Protect from light
Shipping conditions: Ambient
Shelf life: 12 months from date of manufacture

Gibco™ DMEM, high glucose, HEPES, no phenol red

发表于由

上海金畔生物科技有限公司提供Gibco™ DMEM, high glucose, HEPES, no phenol red ，欢迎访问官网了解更多产品信息和订购。
Gibco™ DMEM, high glucose, HEPES, no phenol red

详情介绍

Gibco™ DMEM, high glucose, HEPES, no phenol red

Using DMEM：

DMEM is unique from other media as it contains 4 times the concentration of amino acids and vitamins than the original Eagle's Minimal Essential Medium. DMEM was originally formulated with low glucose (1 g/L) and sodium pyruvate, but is often used with higher glucose levels, with or without sodium pyruvate. DMEM contains no proteins, lipids, or growth factors. Therefore, DMEM requires supplementation, commonly with 10% Fetal Bovine Serum (FBS). DMEM uses a sodium bicarbonate buffer system (3.7 g/L), and therefore requires a 5–10% CO2 environment to maintain physiological pH.


cGMP manufacturing and quality system：

DMEM is manufactured at a cGMP-compliant facility located in Grand Island, New York. The facility is registered with the FDA as a medical device manufacturer and is certified to ISO 13485 standards.


Gibco™ DMEM, high glucose, pyruvate

发表于由

上海金畔生物科技有限公司提供Gibco™ DMEM, high glucose, pyruvate ，欢迎访问官网了解更多产品信息和订购。
Gibco™ DMEM, high glucose, pyruvate

详情介绍

Gibco™ DMEM, high glucose, pyruvate

Using DMEM：

DMEM is unique from other media as it contains 4 times the concentration of amino acids and vitamins than the original Eagle's Minimal Essential Medium. DMEM was originally formulated with low glucose (1 g/L) and sodium pyruvate, but is often used with higher glucose levels, with or without sodium pyruvate. DMEM contains no proteins, lipids, or growth factors. Therefore, DMEM requires supplementation, commonly with 10% Fetal Bovine Serum (FBS). DMEM uses a sodium bicarbonate buffer system (3.7 g/L), and therefore requires a 5–10% CO2 environment to maintain physiological pH.


cGMP manufacturing and quality system：

DMEM is manufactured at a cGMP-compliant facility located in Grand Island, New York. The facility is registered with the FDA as a medical device manufacturer and is certified to ISO 13485 standards. For supply chain continuity, Life Technologies offers an identical DMEM product made in our Scotland facility (41966-029). This facility is registered with the FDA as a medical device manufacturer and is certified to the ISO 13485 standard.


Gibco™ DMEM, high glucose, no phosphates

发表于由

上海金畔生物科技有限公司提供Gibco™ DMEM, high glucose, no phosphates ，欢迎访问官网了解更多产品信息和订购。
Gibco™ DMEM, high glucose, no phosphates

详情介绍

Gibco™ DMEM, high glucose, no phosphates

DMEM is unique from other media as it contains 4 times the concentration of amino acids and vitamins than the original Eagle's Minimal Essential Medium. DMEM was originally formulated with low glucose (1 g/L) and sodium pyruvate, but is often used with higher glucose levels, with or without sodium pyruvate.


Product Use:

For Research Use Only: Not intended for animal or human diagnostic or therapeutic use.


cGMP Manufacturing and Quality System:

Gibco™ DMEM is manufactured at a cGMP compliant facility located in Grand Island, New York. The facility is registered with the FDA as a medical device manufacturer and is certified to ISO 13485 standards.


DMEM contains no proteins, lipids, or growth factors. Therefore, DMEM requires supplementation, commonly with 10% Fetal Bovine Serum (FBS). DMEM uses a sodium bicarbonate buffer system (3.7 g/L) and therefore requires a 5-10% CO2 environment to maintain physiological pH.

Gibco™ DMEM, no glucose, no glutamine, no phenol r

发表于由

上海金畔生物科技有限公司提供Gibco™ DMEM, no glucose, no glutamine, no phenol r ，欢迎访问官网了解更多产品信息和订购。
Gibco™ DMEM, no glucose, no glutamine, no phenol r

详情介绍

Gibco™ DMEM, no glucose, no glutamine, no phenol red

DMEM is unique from other media as it contains 4 times the concentration of amino acids and vitamins than the original Eagle's Minimal Essential Medium. DMEM was originally formulated with low glucose (1 g/L) and sodium pyruvate, but is often used with higher glucose levels, with or without sodium pyruvate.


Product Use：

For Research Use Only: Not intended for animal or human diagnostic or therapeutic use.


cGMP Manufacturing and Quality System：

Gibco™ DMEM is manufactured at a cGMP compliant facility, located in Grand Island, New York. The facility is registered with the FDA as a medical device manufacturer and is certified to ISO 13485 standards.


DMEM contains no proteins, lipids, or growth factors. Therefore, DMEM requires supplementation, commonly with 10% Fetal Bovine Serum (FBS). DMEM uses a sodium bicarbonate buffer system (3.7 g/L) and therefore requires a 5-10% CO2 environment to maintain physiological pH.