On-line preconcentration and determination of chromium in parenteral solutions by flow injection - flame atomic absorption spectrometry

An on-line chromium preconcentration and determination system implemented with flame atomic absorption spectrometry (FAAS) associated to flow injection (FI) was studied. For the retention of chromium, 4-(2-Thiazolylazo)resorcinol (TAR) and Amberlite XAD-16 were used, at pH 5.0. The Cr-TAR complex was removed from the microcolumn with ethanol. An enrichment factor of 50 was obtained for the preconcentration of 50 ml of sample solution. The detection limit value for the preconcentration of 50 ml of aqueous solution of Cr was 20 ng l(-1). The precision for ten replicate determinations at the 5 mug l(-1) Cr levels was 2.9% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9997 at levels near the detection limits up to at least 100 mug l(-1). The method was successfully applied to the determination of chromium in parenteral solution samples. (C) 2002 Elsevier Science B.V. All rights reserved.