title: Trace-level determination of benzidine and 3,3'-dichlorobenzidine in aqueous environmental samples by online solid-phase extraction and liquid chromatography with electrochemical detection.
abstract: A simple, rapid, and reliable online methodology for the determination of benzidine and 3,3'-dichlorobenzidine (3,3'-DCB) in natural waters is proposed. The analytes are extracted and preconcentrated from aqueous samples in a small stainless steel precolumn packed with a polymeric PLRP-S phase. The precolumn is further online-analyzed by reversed-phase gradient-elution chromatography with a highly sensitive and selective coulometric detection at E = 700 mV. Recoveries greater than 90% and a relative standard deviation of approximately 5% are achieved with samples spiked at low micrograms-per-liter concentration levels. The detection limits of the method in fortified reagent water samples are 100 ng/L for benzidine and 50 ng/L for 3,3'-DCB.
authors.affiliation: Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, DF. luzelena@servidor.unam.mx
authors.forename: L E
authors.initials: LE
authors.lastname: Vera-Avila
authors.forename: A
authors.initials: A
authors.lastname: García-Ac
authors.forename: R
authors.initials: R
authors.lastname: Covarrubias-Herrera
mesh_terms: D015101:3,3'-Dichlorobenzidine / Q000032:analysis*; D001560:Benzidines / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D004563:Electrochemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D001560:Benzidines; D014874:Water Pollutants, Chemical; D015101:3,3'-Dichlorobenzidine; C029876:benzidine