title: Determination of phenylurea pesticides by high-performance liquid chromatography with UV and photoconductivity detectors in series.
abstract: High-performance liquid chromatographic (HPLC) separations of eighteen phenylurea pesticides were investigated using both reversed-phase and normal-phase systems. A photoconductivity detector, which responds selectively to ionic products formed via postcolumn UV irradiation of photolabile analytes, was connected in tandem with a UV detector permitting serial dual detection of these compounds. The photoconductivity detector responded selectively to the thirteen halogen and sulfur containing compounds whereas the UV detector responses were of the same order of magnitude for all eighteen compounds at 250 nm. The HPLC-UV-photoconductivity detection system was successfully applied to the determination of chloroxuron in strawberries at the official tolerance level of 0.5 ppm. The tandem detectors combined with a choice of columns and chromatographic modes offers enhanced selectivity for the HPLC analysis of these pesticides as trace contaminants in complex samples.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005506:Food Contamination; D005638:Fruit / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D010671:Phenylurea Compounds / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D010573:Pesticide Residues; D010671:Phenylurea Compounds