Immunoaffinity Extraction-LC-MS Method For Trace Analysis Of Pesticides

Liquid chromatography (LC) with tandem mass (MS/MS) has established its importance in eco-analytical area due to its ultra-low detection limit (~10-14M) and superior qualitative capability. However, it still has limitations. Most notable is the limitation on its application in trace analysis of sample containing complex matrices. Immunoaffinity extraction, enabling simultaneous enrichment and cleanup of the crude sample, is a preferential way to alleviate the limitation above. In this dissertation, the immunoaffinity extraction and LC-MS/MS was combined to determine isoproturon and diuron in complex water samples, and the quantitation of compounds was not found to suffer from the sample matrices.Isoproturon and diuron are the representative phenylureas herbicide, which may enter the drinking water system via atmospheric deposition and rain run-off. For the first time, the anti-isoproturon antibody was encapsulated in a sol-gel matrix to form a immunoaffinity column. The performance of this column was systematically evaluated for sample extraction process. In order to decrease the unspecific binding on sol-gel immunoaffinity column, different methods were tested. Finally, the sol-gel immunoaffinity column can selectively extract isoproturon from an artificial mixture of 63 pesticides. Combined with this immunoaffinity column, LC-MS/MS can provide ng/L level determination of isoproturon in surface water with good linearity and precision. Utilizing the difference activities of two anti-isoproturon monoclonal antibody, a method with tandem sol-gel immunoaffinity columns was established to quantify simultaneously the isoproturon and its metabolite in river.For the first time, the immunoaffinity column with anti-diuron antibody was fabricated. The suitable antibody density in column was determined and the mechanism of elimination of matrix effect by immunoaffinity column wasinvestigated. The on-line immunoaffinity column-LC-MS/MS method can quantify diuron in river and waste water samples without suffering from the sample matrices, this provided a new method for investigating and monitoring of pollutants in ecosystem.