Detecting Melamine In Feed By High-Performance Liquid Chromatography

Melamine is a chemical raw material. Due to its high nitrogen content and the general determination of total nitrogen in the feed and food protein content could not be excluded when the interference of such pseudo-protein nitrogen, it was used by some unscrupulous manufacturers reduce costs, to improve the product protein. At present, it was reported more than have been adding melamine to feed pets Credit death. Therefore, this paper studied the detection of melamine in feed, in order to investigate the rapid detection of melamine in feed. This work is focused on the detection method of melamine in the commercial feed and animals and plants of all kinds of raw materials.The main content of paper is as followed:1. In this paper, C18 column was used for separation. And melamine was well separated with the mobile phase:citric acid- sodium octanesulfonate solution. The concentration,pH and the ratio of organic phase of the ion-pair solution were studied. The results showed that:the low concentration of ion-pair solution,acidic condition(pH=3.0),the low ratio of organic phase could get melamine separated well. In this paper, the mobile phase:0.01M citric acid-sodium octanesulfonate solution:acetonitrile=90:10, pH3.0 was selected.2. The extraction effect of different extraction solution in different feed was Determined. Melamine was weak alkaline. When the pre-treatment method was studied in different feed, methanol:water (V/V)=1:1, acetonitrile:water (V/V)=1:1, acetonitrile: water (V/V)=7:3.1% trichloroacetic acid,1% trichloroacetic acid:acetonitrile (V/V)=4:1 were compared by the effect of the extraction. And the trichloroacetic could precipitate the protein to exclude the interfuse of the impurities. the best extraction solution was 1% trichloroacetic acid:acetonitrile(V/V)=4:1.3. The maximum absorption wavelength was studied in this papaer. Melamine had both maximum absorption wavelength in 210nm and 238nm. But in 210nm, many impurities could interfuse the result, so at last 238nm was choose for the detection of melamine. At the same time, it could make the result more confident with the DAD detector.4. The method was used in detections of different feed samples. The melamie recovery experiments were used for verification. The result showed that, when the addition level of melamine was 2ppm, RSD<5%. When the addition level of melamine was in 1-10ppm, the recovery was over 90%. This method was a reliable way for detection of melamine in different feed samples.5. By using the optimized extraction and chromatographic conditions,64 species of commercial feed and dynamic, natural ingredients were used for melamine testing. The results showed that melamine were not found in feed on the market listed for sale. In this study, there were very little species of natural plant ingredients found the melamine were over standard. The results showed most feed on the market was safe.This study could be used for the rapid detection for melamine in feed, and it was a effective and confident method. Different feed on the market were detected by this method and the result showed that most feed on the market was safe.