Determination of lead in urine by electrothermal atomic absorption spectrometry with probe atomization.

An automated graphite-probe atomizer was used for the direct analysis of diluted (2- to 12.5-fold) urine samples by electrothermal atomic absorption spectrometry (ETAAS). The method was applied successfully to the determination of Pb in reference materials, quality control urines and patient samples. The concentrations found were mainly in the range 7-93 micrograms dm-3 and agreed well with results obtained by an established ETAAS method, which involved chelation of Pb and solvent extraction into isobutyl methyl ketone. The detection limit, based on three times the standard deviation of the blank, was 4 micrograms dm-3 at 283.3 nm and 2 micrograms dm-3 at 217.0 nm. Although probe atomization removed chemical interferences for peak-area measurements, 10-20% suppression remained for some samples with peak-height measurements.