Determination Of Residue Of Chloramphenicol, Zeranols And Aflatoxins In Foodstuffs Of Animal Origin

Two parts were included in this article to study chloramphenicol，zeranols and aflatoxins’ residue analysis in foodstuffs of animal origin.Part Ⅰ Simultaneous determination of zeranols andchloramphenicol in foodstuffs of animal origin by immunoaffinitycolumn clean-up and LC-MS/MS analysisObjective: An immunoaffinity column（IAC）clean-up and liquidchromatography-tandem mass spectrometry (LC-MS/MS) method wassuccessfully developed for simultaneous determination of zeranols(α-zearalanol, β-zearalanol, zearalanone, α-zearalenol, β-zearalenol andzearalenone) and chloramphenicol in foodstuffs of animal origin.Methods:The sample was enzymatic digestion by β-Glucuronidase/sulfatase and then extracted with ether. The extracted solution wasevaporated to dryness and then the residue was dissolved by1mL of50%acetonitrile solution. After filtered，0.5mL filtrate was diluted to5mL withPBS. After clean-up with IAC, the analysis was analyzed by LC-MS/MS.Chromatographic column: Shimaduzu Shim pack-VP-ODS (150mm×2.0mm，5μm). Mobile Phase A was acetonitrile, mobile phase B was2mol/Lammonium acetate solution and containing0.1%formic acid. The gradient elution program: mobile phase A was increased linearly from25%to75%in4min, and keep the ratio of70%from4min to7min, then decreasedlinearly from70%to25%from7.0min to7.5min, and held at this levelfor0.5min so that the system could re-equilibrate before the next injection.Flow rate:0.30mL/min, the column temperature:40℃, the samplequantity:10μL. Mass spectrometry conditions: Negative ionelectrospray-multiple reaction monitoring detection (ESI--MRM);electrospray voltage:-4.5KV; atomizing air pressure:0.24MPa; air curtainair pressure:0.28MPa; assist gas pressure:0.41MPa; ion sourcetemperature:550C. Results: the limit of detection of seven were0.04~0.10μg/kg，the intra-day recoveries were72.2~105.0%, the inter-dayrecoveries were69.1~105.5%, the intra-day relative standard deviations(RSD) were1.0~11.9%, the inter-day RSDs were2.0~13.2%, Matrixeffects (SSE%) were90.8~109.0%. Conclusions: The developed methodis reliable, sensitive and good applicability. The method could be used fordetermination of trace residues of zeranols and Chloramphenicol infoodstuffs of animal origin.Part II Simultaneous determination of zeranols and aflatoxins in milkby immunoaffinity column clean-up and LC-MS/MS analysisObjective: An IAC clean-up and LC-MS/MS method wassuccessfully developed for simultaneous determination of zeranols andaflatoxins (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxinG2, aflatoxinM1and aflatoxin M2) in milk. Methods: After enzymatic digestion byβ-Glucuronidase/sulfatase, the sample was diluted to20mL with PBS andthen passed through glass fiber filter paper. After clean-up with IAC, the analysis was analyzed by LC-MS/MS. LC-MS/MS condition for zeranolswere same to part Ⅰ. LC-MS/MS condition for aflatoxins:chromatographic column: Shimaduzu Shim pack-VP-ODS (150mm×2.0mm，5μm). Mobile Phase A was acetonitrile, mobile phase B was2mol/Lammonium acetate solution and containing0.1%formic acid. The gradientelution program: mobile phase A was kept the ratio of10%from0min to2min, increased linearly from10%to90%in5min, and then decreasedlinearly from90%to10%from9.0min to9.5min, and hold at this levelfor0.5min so that the system could re-equilibrate before the next injection.Flow rate:0.30mL/min, the column temperature:40℃, the samplequantity:10μL. Mass spectrometry conditions: positive ionelectrospray-multiple reaction monitoring detection (ESI+-MRM);electrospray voltage:5.5KV; atomizing air pressure:0.70MPa; air curtainair pressure:0.30MPa; assist gas pressure:0.60MPa; ion sourcetemperature:600C. Results: the limit of detection of eleven were0.01~0.10μg/kg, the intra-day recoveries were77.8~103.2%, the inter-dayrecoveries were72.3~101.6%, the intra-day RSD were1.7~12.4%, theinter-day RSDs were3.5~13.9%, SSE%were98.3~111.5%. Conclusions:The developed method is reliable, sensitive and good applicability. Themethod could be used for determination of trace residues of zeranols andaflatoxins in milk.