Preparation Of GO On-line Purify Solid Phase Extraction Column And Application In Harmful Residues Analysis In Food

Determination of organic residues in food usually requires a solid phase extraction pretreatment to remove impurities and enrich the target.The disadvantages of traditional off-line solid-phase extraction are that the operation is cumbersome,the degree of automation is low,and the adsorbent material is difficult to reuse.In this paper,an on-line purification combined with liquid chromatography-tandem mass spectrometry?LC-MS/MS?method was established to analyze the melamine in milk and 5 organ phosphorus pesticide residues in and fruits and vegetables.The main research content of this article is as follows:1.By optimizing the synthesis method of GO@SiO₂ column,on-line purification conditions and LC-MS/MS experimental conditions,the prepared GO@SiO₂ on-line purification solid-phase extraction column can effectively purify and enrich melamine in milk.the linear and recovery results of the method are satisfactory.the method established in this paper meets the limit detection standards for melamine in China and abroad,and has practical significance.The results showed that the purified GO@SiO₂ online purification solid phase extraction column can effectively purify melamine in milk.The established on-line extraction-HPLC-MS method has good linear and satisfied recovery which can meet the Chinese and International standards for the detection of melamine.2.An on-line purification-liquid chromatography-quadrupole/electrostatic field orbit trap high resolution mass spectrometry method was developed for the determination of five organ phosphorus pesticides in fruits and vegetables.Acetonitrile was selected as the extraction solvent to extract organophosphorus pesticides in carrots,spinach,celery,pears and fruits.The results showed that it is better to use Cyclone-p as an on-line purification column for the purification of 5 organ phosphorus,using 50%acetonitrile as elution solvent.The chromatographic system used 0.1%aqueous acetic acid as the aqueous phase and acetonitrile as the organic phase with gradient elution.5 organ phosphorus pesticides were separated with quantization limit of 2?g/kg,which can meet China's limited requirements for these organ phosphorus pesticide residues.The method is rapid and only takes 13 minutes,which eliminates the tedious pretreatment process,greatly saves the pretreatment time,has good stability and accuracy,high degree of automation,and is conducive to the processing of large batch samples.