Lead determination with on-line enrichment system

The flow injection preconcentration system with a cellulose sorbent was developed to determine trace amounts of lead. The metal was preconcentrated on a microcolumn packed with Cellex P, cellulose sorbent with phosphonic acid groups, and eluted with nitric acid into the nebuliser-burner system of atomic absorption spectrometer. An enrichment factor of 47–197, equivalent of 5.1–25.5 ml of sample, was achieved by using a time-based system. The detection limit (3δ) for 1 min preconcentration time was 1.8 μg l−1 and precision (at 10 μg l−1 level) was 7.8% (RSD). The method was applied to the determination of lead in natural water samples.