On-line preconcentration system coupled to electrothermal atomic absorption spectrometry for the simultaneous determination of bismuth, cadmium, and lead in urine Original Research Article

A laboratory-made flow injection (FI) system coupled to a multi-element electrothermal atomic absorption spectrometer (ETAAS, SIMMA 6000) was used to determine Bi, Cd, and Pb simultaneously in urine. A on-line preconcentration procedure was controlled by a personal computer. A miniature Muromac A-1 resin column was inserted at the top of the AS-72 autosampler arm. A modified AS-72 autosampler in the tubing line and circuit allowed either flow of the sample through the column or operation of the autosampler in the normal mode. Retention of the metal ions as complexes on the microcolumn was achieved by using Muromac A-1 as the chelating resin; 20% (v/v) subboiling HNO3 (50 μl) was then used for elution. The eluate was injected directly into the graphite furnance of the atomic absorption spectrometer. Calibration graphs were constructed using simple aqueous standard in 0.2% (v/v) subboiling HNO3 solution; these were preconcentrated. With a 213 μl sample loop the sample throughput is 10 samples h−1. The 3σ detection limits of this method were 1.3×10−2, 2×10−3, and 4.5×10−3 μg l−1 for Bi, Cd, and Pb, respectively. The accuracy of the method was confirmed by the analysis of a standard reference material (SRM; Seronorm™ Trace Elements Urine) at two concentration levels. The analyzed values were within 90–110% of the reported values.