Determination of arsenic by hydride generation coupled to time-of-flight mass spectrometry with a gas sampling glow discharge

摘要

Hydride generation has been used with a gas-sampling low discharge (GSGD) and time-of-flight mass spectrometry (TOFMS) for the determination of arsenic in solution. Helium, neon, hydrogen, and argon glow discharges have been successfully generated and characterized. Current-pressure-voltage curves were generated for each discharge in the presence of absence of hydride generation. The arsenic detection limit for each of the discharges was found to be 0.60 (HeGSGD), 3.8 (NeGSGD) and 6.4 ppb (H_2GSGD). The HeGSGD was found to be the msot attractive source for arsenic determination due to the lower detection limit, higher sensitivity and greater stability. The figures of merit for these discharges were also compared to those obtained with hydride negeration-inductively coupled plasma TOFMS. Noise power spectra obtained for the neon GSGD indicated that no discernible discrete-frequency (whistle-noise) components were present in the analyte signal.