A method for determining vitamin a, d, e in milk powder

Abstract

The invention relates to a method for measuring vitamin A, D, and E in milk powder, which comprises the following steps: mixing the milk powder sample evenly, weighing an appropriate amount, adding water, absolute ethanol, ascorbic acid, BHT and KOH aqueous solution, heating and saponifying, and saponification is completed After cooling to constant volume; using a high-performance liquid chromatograph equipped with a double-valve three-pump system to measure the content of vitamin A, D, and E in the solution; by comparing the retention time of the sample and the standard substance in the one-dimensional liquid chromatography, confirm that the vitamin A, D, and E in the sample Whether it contains vitamin A, E; by comparing the retention time of the sample and the standard substance in the two-dimensional liquid chromatography, confirm whether the sample contains vitamin D; finally, according to the obtained amount of vitamin A, D, E, calculate the vitamin in the sample after conversion A, D, E content; the invention simplifies the operation steps, greatly shortens the pretreatment time, saves manpower and reagent costs, realizes automatic online purification detection, improves sensitivity, and ensures the accuracy and reproducibility of test results.

Description

[technical field] [0001] The invention belongs to the technical field of analytical chemistry, in particular to a method for determining vitamins A, D and E in milk powder. [Background technique] [0002] Vitamins widely exist in various organisms, and about dozens of types have been discovered so far, with different chemical structures, including aliphatic, aromatic, alicyclic, heterocyclic and steroidal compounds. In terms of physiological functions, they are neither the main raw materials for various tissues nor the source of energy in the body, but they are small molecular organic compounds that are essential to participate in the mediation of substance metabolism. Vitamins A, D, and E are all non-polar hydrophobic isoprene derivatives, soluble in lipids and fat solvents, but insoluble in water, and belong to fat-soluble vitamins. Excessive intake, unbalanced intake or lack of intake will cause corresponding symptoms, affecting the growth and development of the body and...

AI Technical Summary

Problems solved by technology

[0005] In 2013, Wang Anqun et al. reported a method for the determination of vitamin A, D3, and E in feed by high-performance liquid chromatography in the journal "Environmental Monitoring Management and Technology". The matrix is ​​complex, which seriously damages the chromatographic column. At the same time, the low VD content is easily interfered by the matrix and cannot be detected, so it is difficult to popularize

However, its pre-treatment must be avoided through saponification, wall-breaking extraction, organic solvent phase inversion, and concentration of these tedious processes

Although the two-dimensional column switching method solves the problem of matrix interference, due to the diffusion phenomenon of the target substance in the process of chromatographic distribution, it is easy to broaden the chromatographic peak and cannot be detected. Obviously, it is difficult to reduce the detection limit of VD, which cannot meet the test requirements of low-content samples

In 2015, Yangzhou Institute of Quality Inspection reported a method for testing vitamin A, D, and E in milk powder by high performance liquid chromatography tandem mass spectrometry. Although the sensitivity of the method has been improved, the pretreatment process still cannot avoid saponification extraction and organic solvent phase conversion concentration, etc. step

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