Ultratrace determination of lead by hydride generation in-atomizer trapping atomic absorption spectrometry: Optimization of plumbane generation and analyte preconcentration in a quartz trap-and-atomizer device

Abstract

A compact trap-and-atomizer device and a preconcentration procedure based on hydride trapping in excess of oxygen over hydrogen in the collection step, both constructed and developed previously in our laboratory, were employed to optimize plumbane trapping in this device and to develop a routine method for ultratrace lead determination subsequently. The inherent advantage of this preconcentration approach is that 100% preconcentration efficiency for lead is reached in this device which has never been reported before using quartz or metal traps. Plumbane is completely retained in the trap-and-atomizer device at 290°C in oxygen-rich atmosphere and trapped species are subsequently volatilized at 830°C in hydrogen-rich atmosphere. Effect of relevant experimental parameters on plumbane trapping and lead volatilization are discussed, and possible trapping mechanisms are hypothesized. Plumbane trapping in the trap-and-atomizer device can be routinely used for lead determination at ultratrace levels reaching a detection limit of 0.21ngml−1 Pb (30s preconcentration, sample volume 2ml). Further improvement of the detection limit is feasible by reducing the blank signal and increasing the trapping time.