Simultaneous determination of Cr, Ga, In and V in soil and water samples by tungsten coil atomic emission spectrometry

Abstract

Tungsten coil atomic emission spectrometry is employed for the simultaneous determination of Cr, Ga, In, and V. Both V and In are detected by this technique for the first time. The atomizer is a simple, inexpensive tungsten filament extracted from a mass-produced, commercially-available 150 W, 15 V microscope bulb. A 25 µl sample aliquot is placed directly on the coil and a small constant-current power source is used to carefully dry, ash and atomize the sample. Analytical signals are detected with a Czerny-Turner spectrograph and a charge coupled device detector. Multiple emission lines from all 4 elements are monitored simultaneously in a 54 nm spectral window. Concentration limits of detection are in the µg l − 1 range for all elements, and the absolute limits of detection are 0.2, 2, 0.5, and 10 ng for Cr, Ga, In, and V, respectively. Even lower values may be obtained by combining the signals for the multiple emission lines of a single element. The method precision is typically better than 5.0% relative standard deviation, and sometimes as good as 0.95% (Ga). Standard reference materials of soil and water are used to check the method accuracy. After a simple acid extraction, the values determined by the method presented no significant difference from the reported values at the 95% confidence level.