Method for synchronously detecting L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder

A technology of dehydroascorbic acid and ascorbic acid, which is applied in the direction of measuring devices, instruments, scientific instruments, etc., can solve the problems of reduced resolution, unfavorable precise determination and quantification, and retention time drift, so as to improve stability, prolong life, and avoid mutual interference effect

Inactive Publication Date: 2018-02-06
山东世通检测评价技术服务有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Determination of L-AA, D-AA, and DHA in milk powder using the current chromatographic conditions usually has the problem that as the concentration of ascorbic acid increases, the separation degree of L-AA and D-AA decreases, and even a flat peak appears, and the retention time drifts. Conducive to precise identification and quantification ( figure 1 )

Method used

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  • Method for synchronously detecting L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder
  • Method for synchronously detecting L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder
  • Method for synchronously detecting L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder

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Effect test

Embodiment 1

[0114] Present embodiment is the mensuration of ascorbic acid in goat milk powder:

[0115] 1. Selection of mobile phase

[0116] In view of the fact that the existing chromatographic conditions cannot effectively separate the two ascorbic acids, the applicant used an equal volume of potassium dihydrogen phosphate and decylamine as the mobile phase. The impact on the peak shape and separation effect of the two ascorbic acids is shown in Table 1 for the composition of the buffer salt. , see the chromatogram Figure 5 .

[0117] Table 1 buffer salt concentration

[0118]

[0119] Depend on Figure 5 In a, b, and c, it can be seen that with the increase of the concentration of decylamine, the resolution is improved. When the concentrations of potassium dihydrogen phosphate and decylamine are 0.05mol / L and 8.6mmol / L respectively, the resolution is better, but too high a buffer salt concentration will shorten the service life of the chromatographic column. Therefore, potassi...

Embodiment 2

[0172] Present embodiment is the mensuration of ascorbic acid in formula milk powder:

[0173] 1. Sample pretreatment:

[0174] Preparation of liquid A: Weigh 2-3g formula milk powder sample (accurate to 0.001g) and place it in a centrifuge tube with stopper, add 0.25mol / L metaphosphoric acid and 0.019mol / L sodium thiosulfate mixed extract, vortex to dissolve And dilute to 25ml. Shake well, sonicate in an ice bath for 3 seconds, pause for 5 seconds, 90-100 cycles; centrifuge at 0°C and 9000r / min for 5 minutes, absorb part of the supernatant, and the other part of the supernatant is used for the preparation of B solution, and pass through the 0.22μm water phase Transfer to a brown bottle after membrane filtration for determination of L-ascorbic acid and D-ascorbic acid content;

[0175] Preparation of liquid B: Take 10ml of the centrifuged supernatant from part A in a centrifuge tube with stopper, add 5ml of L-cysteine ​​solution with 0.177mol / L, and adjust the pH to 7.0-7.2 ...

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Abstract

The invention provides a method for synchronously detecting L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder. According to the method, deoxidized sodium thiosulfate and metaphosphoric acid mixed solution is used as an extracting liquid, active ascorbic acid can be effectively protected, the stability of the ascorbic acid can be improved, light-resistant operation is not required, experimental operation is simple and convenient, and the extract has stable property in 24 hours at low temperature. The chromatographic condition has small damage to a chromatographic column,and the service life of the chromatographic column can be prolonged; a mobile phase is formed by monopotassium phosphate and decyl amine, the resolution can be improved by the concentration of the mobile phase, two geometric isomers can still be effectively separated when the ascorbic acid has relatively high concentration, mutual interference can be avoided, and the content of active ascorbic acid can be accurately detected. The method has the advantages of simple operation, small chemical reagent dosage and good extract stability, has a relative standard deviation of 7.82 percent, can be used for multi-union detection, and has an important meaning for accurately detecting the true content of active ascorbic acid in milk powder.

Description

technical field [0001] The invention belongs to the technical field of food testing, in particular to a method for synchronously measuring L-ascorbic acid, D-ascorbic acid and dehydroascorbic acid in milk powder. Background technique [0002] Vitamin C (also known as L-ascorbic acid, L-AA) is a vitamin with the largest daily dietary recommended supply for the human body. The human body cannot synthesize it by itself, and it is mainly ingested from food. There are two types of L-ascorbic acid, reduced form and dehydrogenated form. The reduced form is extremely unstable and easily oxidized into dehydroascorbic acid (DHA). D-ascorbic acid (D-AA) is an optical isomer of L-AA, which is often used as a food additive, but its activity is only 5% of that of L-AA. Therefore, in order to accurately determine the content of ascorbic acid in milk powder and evaluate its antioxidant value, it is necessary to distinguish L-AA, D-AA, and DHA. [0003] At present, the determination method...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/89G01N30/06G01N30/14G01N30/86
CPCG01N30/06G01N30/14G01N30/8634G01N30/89G01N2030/146
Inventor 孙海新崔玲君孙丕春周延培张慧
Owner 山东世通检测评价技术服务有限公司
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