Application Of Fast Sample Pre-treatment Techniques In Determination Of Multi-component Such As Mycotoxins In Foodstuffs

Mycotoxins are secondary metabolites produced by filamentous fungi under suitable conditions.Several common mycotoxins in food were reviewed in terms of species and toxicities,as well as pre-treatment technology,detection and experimental design methodologies.This research focused on introduction and application of QuEChERS extraction,dispersive liquid-liquid microextraction(DLLME),ultra-high performance liquid chromatography(UPLC),ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),Plackett-Burman design and response surface methodology(RSM),etc.The main contents and highlights are listed as follows:(1)A simple and reliable method of ultra high performance liquid chromatography-isotope dilution mass spectrometry has been proposed for simultaneous determination of deoxynivalenol and its acetylated derivatives in foodstuffs: Sample pretreatment consisted of a first step using acidic acetonitrile extraction and a subsequent cleanup step based on multi-function column or solid-phase extraction.Satisfactory linearity with R2 >0.999 was achieved in the range of 5-1280 ?g/kg.Limits of detection(LODs)and limits of quantita tion(LOQs)were 6 ?g/kg and 20 ?g/kg,respectively.Recoveries of 79.36-111.8% with RSD<12.50% were achieved in three typical matrices.(2)A novel pre-treatment was proposed for simultaneous determination of aflatoxins,ochratoxin A and zearalenone in foodstuffs using chromatographic technique.The analytical procedure was based on QuEChERS-based extraction,salting out and purification with a C18 solid phase extraction column as interference removal solid phase extraction.Subsequently,the collected supernatant was subjected to DLLME.Hereinto,RSM based on central composite design was employed to optimize conditions in DLLME procedure.Finally,the LODs of 0.03 ?g/kg-13 ?g/kg,LOQs of 0.22 ?g/kg-44 ?g/kg and recoveries between 63.22%-107.6%(RSD<8.13%)were obtained.(3)A novel pre-treatment method based on Q uEChERS extraction and DLLME followed by UPLC coupled with ultraviolet/fluorescence detection was developed for simultaneous determination of five Alternaria toxins in cereal foodstuffs.RSM based on central composite design was employed to optimize the microextraction conditions.The LODs were between 0.62 ?g/kg and 48 ?g/kg while LOQs between 2.1 ?g/kg and 120 ?g/kg.The recoveries for three spike levels were higher than 72.69%(RSD<9.62%).(4)A multi-residue method was proposed for the simultaneous determination of 104 contaminants in eggs and milk by UPLC-MS/MS.The pretreatment procedure was based on a first step using QuEChERS-based extraction,followed by salting out and purification with C18,PSA and anhydrous NaSO4.Plackett-Burman design was employed for screening of significant factors and then RSM based on central composite design was conducted for optimization.During the validation,the recoveries of most mycotoxins and quinolones were about 80%,sulphonamides about 60% and other drugs between 30% and 110%.The methodological LOQs were between 0.01 ?g/kg-31 ?g/kg.