- 维生素C[L-抗坏血酸]检测试剂盒
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英文名：L-Ascorbic Acid (L-Ascorbate)
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货号：K-ASCO
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规格：40 assays (manual) / 400 assays
- Very competitive price (cost per test)
- All reagents stable for > 6 months after preparation
- 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
- Ensure that you have tested the standard sample that is supplied with the Megazyme test kit.
市场价： 2438元
分析物意义： 蔬菜水果中的天然成分或加工食品中的添加成分
Megazyme检测试剂盒优点：反应快、试剂稳定
For the specific assay of L-ascorbic acid in beverages, meat, flour, dairy and vegetable products. Content:40 assays per kit
Colourimetric method for the determination of L-Ascorbic Acid
in foodstuffs, feed, wine and other materials
Principle:
(5-methylphenazinium methosulphate)
(1) L-Ascorbic acid + R-H2 + MTT → dehydroascorbate + MTT-formazan + H+
(ascorbic acid oxidase)
(2) L-Ascorbic acid + ½O2 → dehydroascorbate + H2O
Kit size: 40 assays (manual) / 400 (microplate)
/ 400 (auto-analyser)
Method: Spectrophotometric at 578 nm
Reaction time: ~ 8 min
Detection limit: 0.175 mg/L
Application examples:
Wine, beer, fruit juices, soft drinks, jam, milk, dairy products
(e.g. cheese), dietetic foods, baby foods, processed meat, baking
additives, fruit and vegetables (e.g. tomato and potato),
pharmaceuticals, feed and other materials (e.g. biological cultures,
samples, etc.)
Method recognition:
Methods based on this principle have been accepted by MEBAK
Advantages
Q1. Is it possible to adapt the kit for use on various auto-analysers?
Yes. If the assay format is not available for your auto-analyser you can supply the following parameters of your relevant auto-analyser to Megazyme and an appropriate assay format may be available:
Parameters:
Instrument make and model:
Light-path length:
Reagent addition volumes (e.g. R1 volume, R2 volume, R3 if applicable):
Suggested auto-analyser format for K-ASCO:
Prepare the reagents as described in the K-ASCO data booklet then prepare R1 and R2 as follows:
Preparation of R1: (90 assays)
|
Component |
Volume |
|
Bottle 1 |
5.6 mL |
|
Bottle 4 |
0.225 mL |
|
Distilled water |
17.5 mL |
|
Total volume |
23.325 mL |
Preparation of R2: (90 assays)
|
Component |
Volume |
|
Bottle 2 |
2.25 mL |
|
Bottle 3 |
2.25 mL |
|
Total volume |
4.5 mL |
EXAMPLE METHOD:
R1: 0.260 mL
Sample: ~ 0.005 mL
R2: 0.05 mL
Note: For accurate measurement of ascorbic acid each sample requires two measurements, one with AAO (bottle 4) present and one with AAO (bottle 4) absent.
In the auto-analyser format described above there is no option to read A1 as in the cuvette assay. In this instance use an ascorbic acid calibration curve to calculate results. Alternatively add 0.025 mL of bottle 2 and 3 separately to mimic the cuvette assay and allow the reading A1 (this will require 3 reagent additions) OR it may be possible to add the MTT (bottle 2) with R1 as follows:
Preparation of R1: (90 assays)
|
Component |
Volume |
|
Bottle 1 |
5.6 mL |
|
Bottle 2 |
2.25 mL |
|
Bottle 4 |
0.225 mL |
|
Distilled water |
17.5 mL |
|
Total volume |
25.575 mL |
Preparation of R2: (90 assays)
|
Component |
Volume |
|
Bottle 2 |
2.25 mL |
|
Bottle 3 |
2.25 mL |
|
Total volume |
4.5 mL |
EXAMPLE METHOD:
R1: 0.285 mL
Sample: ~ 0.005 mL
R2: 0.025 mL
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. 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: