Determination of Trace Amounts of Chromium in Human Urine by Flameless Atomic Absorption Spectroscopy

Atomic absorption spectroscopic method for the determination of ppb levels of chromium in human urine was investigated by using the technique of a carbon tube atomizer to provide a simple and rapid means for the quantitative determination of total chromium. In order to establish the optimum conditions for the determination of chromium in a sample, various factors such as atomization efficiency including ashing or drying conditions, effect of acids, and matrices were studied. Under the optimum conditions established, the detection limit of the method for S/N = 2 was evaluated as 2×10-11 g and the linearlity of the absobance vs. concentration was good up to 3 ng of chromium. The precision was estimated to be 2.65% (relative standard deviation) from the results of 10 injections of 50 μl of synthetic urine solution containing 20 ppb of chromium, and the recovery of chromium added to synthetic and human urine samples before wet ashing was in the renge of 95-104%. Interference by matrices such as salts and organics in the samples could be eliminated by this technique of double atomization. Chromium concentration in urine from 13 normal subjects ranged from 0.4 to 26.4 ng/ml, which is similar to recent values obtained by several workers.