Development Of Screening Method For Unknown Compounds, Focusing On Pesticide And Veterinary Drug Residues In Foodstuffs By Quadruple Time Of Flight Mass Spectrometry

With the rapid development of agriculture and animal husbandry, more and more pesticidesand veterinary drugs are widely used in the practices. There are many residues and metabolites ofcompounds around human beings thanks to abuse and misuse for productions. Consequently, alot of harmfulness has generated. In recent years, there were the frequent repots concerning foodsafety, but what worried us most were the contaminated foodstuffs with pesticides and drugs.People and government showed their anxiety on unprecedented level of food safety, and hope tohave more determination technologies for residues. Currently, most techniques for residuedetermination focus on the analysis of known compounds in foodstuffs, and they might notmatch the requirements for food safety. It is important to develop a procedure for the screeningof those unknown compounds.In this study, pretreatment methods including extraction and purification were performedunder different conditions. More than six sets of solvents, including methanol, methanol,acetonitrile, acetone, ethyl acetate, formic acid/acetonitrile (1:99,V/V), and acetate inacetonitrile with different volume, were selected to evaluate the efficiency of extraction foranalytes. The result indicated that the effect with acetate in acetonitrile (1:99, V/V) was higherthan others. In the procedure for pesticide analysis, PSA, C18and GCB were used to decreaseorganic acids, pigments and fat compounds. For the analysis of veterinary drugs, PSA andC18EC were utilized to reduce lipids, proteins, organic acids and sugars in matrix.A procedure was developed by liquid chromatography/quadruple time of flight massspectrometry (LC-Q-TOF MS). The full scan rang was100-1000, and10product ion scans wereconducted at the same time, with the help of IDA(information dependent acquisition). The datawere preceded on the software Peakview, with information including molecular weight, isotopematching, retention time, and MS/MS.The proposed method of QuEChERS-LC-Q-TOF-MS was used to the screening analysisof unknown compounds,focusing on pesticides and veterinary drugs in foods. Samples wereextracted with acetate in acetonitrile (1:99, V/V), and purified with PSA, C18and GCB (onlyfor pesticides). In the spiked experiments, the recoveries of plant-origin products and animal-origin foods were range from71.7%to95.9%and57.3%to73.6%, respectively, withthe RSDs of2.6%to6.6%and1.3%to3.1%, respectively. The LOQs ranged from0.1to1.0μg/kg. The result showed that all indicators from the experiment matched requirements forresidue analysis. In the practices of samples from local market, organophosphorus,carbamate,and nicotinamide pesticides were found in plant products, β-agonistes andsulfanilamides were detected in pork samples, and malachite, fluroquinoloncs andsulfanilamides were probed in aquatic products.The proposed method is easy, cheap, rapid,sensitive,accurate and selective for screeningmultiple pesticide and veterinary drug residues in animals and plants.