Development of an atomic fluorescence spectrometer for the hydride-forming elements

A novel atomic fluorescence spectrometer is reported for the determination of hydride-forming elements, principally arsenic and selenium. A miniature argon–hydrogen diffusion flame was used as the atomizer and the analyte elements were introduced as their gaseous hydrides from a fully automated continuous hydride generator. The hydrogen for the flame was chemically generated as a by-product of the sodium tetrahydroborate reduction. Excitation was achieved using a boosted-discharge hollow cathode lamp. Fluorescence wavelengths of interest were selected using an interference filter. A solar blind photomultiplier was used as the detector. The instrument is notably compact and capable of full automation by connection to a personal computer using a DIO card. Optimization of the instrumentation is described. Detection limits (3σ) of 0.10 and 0.05 µg l–1 for arsenic and selenium, respectively, are reported, as are a number of analyses of certified reference water samples, which confirm the excellent accuracy and precision of the new instrumentation.