Preconcentration and speciation of chromium in drinking water samples by coupling of on-line sorption on activated carbon to ETAAS determination.
An on-line flow injection (FI) preconcentration-electrothermal atomic absorption spectrometry (ETAAS) method is developed for trace determination of chromium in drinking water samples by sorption on a conical minicolumn packed with activated carbon (AC) at pH 5.0. The chromium was removed from the minicolumn with 1.0% (v/v) nitric acid. An enrichment factor (EF) of 35-fold for a sample volume of 10ml was obtained. The detection limit (DL) value for the preconcentration method proposed was 3.0ngl(-1). The precision for 10 replicate determinations at the 0.5mugl(-1) Cr level was 4.0% relative standard deviation (R.S.D.), calculate with the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9992 at levels near the detection limits up to at least 50mugl(-1). The method was successfully applied to the determination of Cr(III) and Cr(VI) in drinking water samples.
Gil
R A
RA
Department of Analytical Chemistry, Faculty of Chemistry, Biochemistry and Pharmacy, National University of San Luis, Chacabuco and Pedernera, P.O. Box 375, 5700 San Luis, Argentina.
Cerutti
S
S
Gásquez
J A
JA
Olsina
R A
RA
Martinez
L D
LD