Application Of Capillary Electrochromatography With Laser Induced Fluorescence Detection For Analysis Of Peptide Antibiotics Residues

As a new antibacterial and insecticidal antibiotic,peptide antibiotics have been widely used in the feed additives and veterinary drugs of poultry,swine,cattle,et al.With the rapid development of animal husbandry,the residues in animal body and prolonged exposure of peptide antibiotics may be harmful to the food safety and make bacterial resistance more seriously.However,there is still lack of an analysis method for peptide antibiotics with high sensitivity and specificity,due to the low content and high matrix interference in samples.Capillary electrochromatography(CEC)coupled to laser induced fluorescence detection(LIF)is a hyphenated technique that possesses high selectivity,high separation efficiency and high sensitivity.Furthermore,the combination of it with micro-extraction technique provides an effective approach for the trace analysis of analytes.This paper aims to establish a new method for the analysis of trace peptide antibiotics residues,and improve the detection sensitivity of peptide antibiotics by coupling with ionic liquids-based polymer monolith microextraction.The thesis includes the following three parts:In chapter 1,the type,function and harmfulness of polypeptide antibiotics residue were described.The states of peptide antibiotics research including separation and sample pre-treatment methods were introduced.The principle of capillary electrochromatography and its related hyphenated detection techniques,especially laser induced fluorescence were overviewed.The application of polymer capillary monolithic column for micro-extraction was reviewed.Finally,research content and significance of this thesis were proposed.In chapter 2,a pCEC-LIF method for bacitracin,polymyxin B and colistin in animal feeds and milk was proposed,using phenyl-based reverse phase capillary packed column as separation stationary phase and 7-fluoro-4-nitrobenz-2-oxa-1,3-diazole(NBD-F)as efficient fluorescence reagent.Under the optimized derivitization and separation conditions,three peptide antibiotics were separated within 25 min,with a linear range of 10.0-1000.0μg/L.The limits of detection(S/N=3)were 5.0-10.0μg/L,that meet the maximum residues limits of polypeptide antibiotics.The proposed method showed high sensitivity,easy handle and significantly lower costs compared with MS detection.In chapter 3,an ionic liquid modified polymer monolithic column for micro-extraction was prepared with HEMA as functional monomer.It can be applied to the extraction and enrichment of colistin.A high sensitive coupling method of ILs-based PMME and CEC-LIF was established,and applied to the analysis of colistin in meat samples.The analyte was completely separated from the matrix,and eluted within 15 min,with a concentration linear range of 1.0-2000.0 μg/L.The limit of detection(S/N=3)was 0.5 μg/L,and the mean recoveries were 75.8%to 86.5%.This method provides a novel and effective way for the determination of peptide antibiotics residues in complex samples.