Method for determining content of free chromium in chromium chelate preparation by using ion exchange chromatography

Abstract

The invention provides a method for determining the content of free chromium in a chromium chelate preparation by using ion exchange chromatography. The method comprises the following steps: adding a solution of a chromium chelate preparation sample into a cation exchange chromatographic column; eluting unadsorbed chromium chelate with deionized water; then eluting free chromium with a highly acid solution; and calculating the content of free chromium in the chromium chelate preparation. The method is simple to operate and has low requirements on experimental apparatuses; ion exchange resin can be repeatedly used; and the method has good reproducibility and stability, good precision, high accuracy and low detection limit, as low as 1 ppm, and is beneficial for further monitoring of the quality of the feed additive the chromium chelate preparation and for animal culture and food safety.

Description

technical field [0001] The invention belongs to the technical field of element content detection, and in particular relates to a method for measuring free chromium content in chelated chromium preparations by ion exchange chromatography, which is mainly used for the determination of free chromium content in feed additive chelated chromium preparations. Background technique [0002] Chromium is one of the essential trace elements in animals. It participates in the metabolism of sugar, fat and protein in animals, and plays a significant role in relieving stress in livestock and poultry, improving immunity, improving reproductive performance, improving carcass quality, and promoting growth. The core role of chromium lies in its important role in all insulin regulation activities. It can help insulin promote the efficiency of glucose entering cells, and is an important blood sugar regulator. [0003] The absorption of chromium has a lot to do with the form of chemical combinatio...

AI Technical Summary

Problems solved by technology

Trivalent chromium is usually chromium trioxide (Cr 2 o 3 ) and chromium salts (such as chromium sulfate Cr 2 (SO 4 ) 3 , chromium nitrate Cr(NO 3 ) 3 and Chromium Chloride CrCl 3 ), the trivalent chromium ion is stable in acidic medium and is not easily oxidized, but in neutral and alkaline medium, its redox stability is greatly reduced, and it can even be oxidized by O in the air. 2 Oxidized to hexavalent chromium, which is highly toxic and has an accumulation effect in animals

Scientific research has found that hexavalent chromium compounds have carcinogenic effects in the body and can cause many other health problems. Ingestion of large doses of chromium can lead to kidney and liver damage, nausea, gastrointestinal irritation, gastric ulcers, cramps and even death , Skin contact can cause ulcers or allergic reactions (hexavalent chromium is one of the metals that are most likely to cause allergies, second only to nickel), according to experimental studies, it has been shown that feeding mice with large doses of hexavalent chromium will affect the reproduction of mice. have an effect, resulting in a reduction in the number of litters and a decrease in fetal weight

[0005] Chelated chromium such as chromium picolinate and chromium nicotinate used as feed additives are composed of inorganic chromium salts (such as CrCl 3 , Cr (NO 3 ) 3 etc.) and picolinic acid, nicotinic acid and other organic substances chelated, so there may be free inorganic C in the final product r 3+ Existence, especially when there is a mistake in the reaction process or when it is not well controlled, Cr in the product 3+ The content of free chromium will increase significantly, and these trivalent free chromium will be easily oxidized to hexavalent chromium by oxygen and oxidative substances contained in the feed after entering the feed, which will cause harm to animals, or enter the animal body due to accumulation in the animal body. in meat products, thereby posing a threat to human health