| Zearalenone and its metabolites,belonging to non steroidal hormones,are of estrogenic effects,immune toxicity,and reproductive-development toxicity which could impact the health of animals and humans,and should gain a strict monitoring.Pressurized capillary electrochromatography(pCEC),a new technology based on both capillary electrophoresis(CE)and high performance liquid chromatography(HPLC),provides a feasible method for trace analysis of hormone-like substance due to its simplicity and ultra-low sample and solvent consumption with high resolution and efficiency.In this thesis,by using pCEC method,the separation behavior and on-line enrichment technique of zeranol hormones were investigated,and a new approach to effcicient analysis of trace zeranol hormones has been formed.There are four chapters in this thesis and shows as below:In chapter 1,a review on the mechanism of pCEC and the development on improving the analysis sensitivity has been introduced.Properties,characteristics and analysis methods for zearalenone and its metabolites have been summarized,and thus the topic and research content of this work were proposed.In chapter 2,the separation behavior of zearalenone and its metabolites on RP-C18 capillary column were studied by pCEC.Effects of experimental parameters including organic solvent,running buffer and the voltage were investigated.Under the optimal conditions,an effeciant profile for zeranols hormones by pCEC method was established.A baseline separation of five analytes(viz.β-ZAL,β-ZOL,α-ZAL,ZAN and ZON)could be obtained within 12.0 minutes with RSD values of migration time less than 3.8%,the limit of detection(S/N=3)was of 1.0 μg/mL.Applied to pork samples with the spiked concentrations of 3.0 mg/kg and 10.0 mg/kg,the mean recoveries were obtained in the range from 66.3%and 82.4%.The results were acceptable and in line with that of HPLC-UV method.In chapter 3,the on-line enrichment of ZON on capillary column was evaluated by pCEC method.Based on the field-amplified injection(FASS)and chromatographic zone-sharpening effect(CZSE),effects on enrichment parameters including organic solvent,sample matrix composition,separation voltage,column pressure,and injection volume were investigated in detail by using ZON as a model solute.Under the optimal condition,an on-line enrichment technology for ZON hormone was established.A low limit of detection(LOD)was gained and up to 0.005 μg/mL,which could increase three orders of magnitude in sensitivity when compared to that of traditional injection mode.In chapter 4,a method for continuous separation and detection of traces zearalenone and its metabolites has been evaluated by pCEC with on-line enrichment.The parameters influencing the sensitivity and mechanism,including sample solvent,injection volume,separation voltage,injection time were studied systematically.A highly sensitive profile for zeranol hormones coupled with on-line enrichment with large volume injection was obtained with the detection limit of 0.001 μg/mL.Compared to conventional UV detection method,better detection ability with the sensitivity could be provided by this on-line enrichment method and raised up to 1000-fold.Applied to fortified pork samples with the concentrations of 75.0 μg/kg and 150.0 μg/kg,respectively,the mean recoveries wre gained in the range of 63.6～97.4%,and RSD was less than 9.6%. |
