Immobilized chloroxine as a preconcentration reagent for atomic absorption spectrometry

A now injection system combining on-line preconcentration with immobilized chloroxine and spectrophotometric detection was developed for trace metal determination. The chloroxine was immobilized onto a silanized control pore glass substrate which showed excellent stability. The reagent was packed into a minicolumn and used to preconcentrate Cu2+, Zn2+, Cd2+, Co2+, and Pb2+ The enhancement in sensitivity was on the order of 49-136 times better than that for direct injection, using a 5-ml sample with a sampling rate of 20 h(-1). (C) 1996 Academic Press, Inc.