Direct determination of chromium in urine by electrothermal atomic absorption spectrometry.

A simple, direct method for the determination of chromium levels in urine is described, electrothermal atomic absorption spectrometry having been used after the urine samples had been acidified. The optimal conditions at the ashing and atomization stages was determined. The detection limit of this method is 5 nmol/1, and the coefficient of variation (within day) is about 3% in the concentration range 20--400 nmol/1. Use of a low temperature asher with electrically excited oxygen before analysis gave results similar to those of the direct procedure. Good correlation was obtained from two other laboratories using different instruments and pretreatments.