Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 7, July 2001, pp. 301-307
Trace-Level
Determination of Benzidine and 3,3'-Dichlorobenzidine in Aqueous Environmental
Samples by Online Solid-Phase Extraction and Liquid Chromatography with Electrochemical
DetectionLuz
E. Vera-Avila*, Araceli García-Ac, and Rosario Covarrubias-Herrera
Departamento de Química Analítica, Facultad de Química,
Universidad Nacional Autónoma de México, 04510 México D.F.,
Mexico
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.
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