Research On Analytical Methods For Screening Mixed Contaminants In Eggs

China is one of the largest countries in producing and consuming eggs in the world.The high density of laying hen production caused an increase in morbidity and mortality.Some pesticides and veterinary drugs were also used for treat the disease or as feed additives,or improve the sanitation of breeding environment,thereby increasing the risk of drug residues in eggs and posing a potential hazard to human health.Therefore,the establishment of methods for determination a variety of chemical contaminants in eggs is of great significance for safeguarding the quality and safety of egg products while reducing the eaten risky.In this thesis,three methods were developed for analysis of various chemical contaminants in eggs through the liquid chromatography combined with triple quadrupole mass spectrometry or high resolution tandem mass spectrometry,it provides an important technical means for rapid screening and determination of pesticide and veterinary drug residues in eggs.The main research contents are summaried as follows:Firstly,an ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry(UHPLC-QQQ-MS/MS)method for rapid determination of 58 pesticides and metabolites in eggs was established.The egg sample was extracted with 5mL water and 10 mL 1% acetic acid in acetonitrile and then salt out with sodium chloride.The extracted solution was filtered directly through an multi-functional filter(MFF)which containing 50 mg PSA,50 mg C18,and 150 mg magnesium sulphate before analysis.Good linearity was shown for each analyte,and all the correlation coefficients(r)exceeded 0.9947.The recoveries in the eggs were 74.4%-115.2%,and the relative standard deviations(RSD)were less than 15.3%.The limit of detection(LOD)and the limit of quantitation(LOQ)of 58 compounds in eggs were 0.1-1.0?g/kg and 0.2-5.0?g/kg,respectively.The decision limit(CC?)and detection capacity(CC?)were 3.4-111.1?g/kg and 6.8-122.1?g/kg,respectively.This developed method is more effective and faster in the monitoring of pesticide residue in eggs compared to the traditional analytical methods.Based on this established method,the stability of 46 compounds in eggs frozen for 7 consecutive days was investigated.The results showed that the recoveries of 22 compounds were always between 70% and 120%,which could detected within 7 days and the results have no significant impact,thus providing a time basis for sample preparation and detection of egg samples.Secondly,a multiclass method was developed for the simultaneous determination of 244 chemical contaminants in eggs by UHPLC-QQQ-MS/MS.The categories of compounds covered by ?-adrenergic receptors(25),imidazoles and benzimidazole(31),sulfonamides(22),antihistamine drugs(10),?-lactam antibiotics(5),insecticides(7),quinolones(24),non-steroidal anti-inflammatory drugs(13)and steroid hormones(38),etc.Sample was extracted with 5% formic acid in acetonitrile and using EMR-Lipid to clean-up.Validation results according to the European Union(EU)2002/657/EC and SANTE/11813/2017 are as follows: r>0.9905,the recovery was between 51.3% and 18.3% in three fortified levels and RSD<15.0%,CC? and CC? were in the range of 1.9?g/kg to 40.6?g/kg and 2.9?g/kg to 407.2?g/kg,respectively.This method has also been successfully applied in the determination of actual eggs samples.Finally,an analytical method was developed for screening 158 chemical contaminants in eggs by ultra high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UHPLC-Q-TOF-MS).The types of drugs were involved ?-adrenergic receptors(16),sulfonamides(15),antihistamine drugs(10),imidazoles and benzimidazoles(19),insecticides(7),non-steroidal anti-inflammatory drugs(9),quinolones(7),stimulants(2),steroid hormones(28)and so on.A secondary mass spectrometry library of 180 chemical contaminants was established by information dependent acquisition(IDA)scanning mode.When EMR-Lipid was used to purify samples,158 compounds can be screened out simultaneously.The results showed that the correlation coefficient of all compounds was greater than 0.9901,the screening detection limit(SDL)was between 0.1?g/kg and 5?g/kg.When the fortified concentration were 5?g/kg,10?g/kg and 50?g/kg,the recoveries were ranged from 50.5% to 88.9% and RSD<13.1%.This method has high sensitivity and provided an important quantitative tool for rapid screening of chemical contaminants in eggs.