Cd and other heavy metals are toxic for humans and other organisms. This creates a need for new methods to detect heavy metals in environmental samples. Cd can be, among others, determined by atomic spectrometric methods after the generation of its hydride. The main drawback of this method is the use of the reducing agent, sodium borohydride, which is unstable in solution requiring its daily preparation. A new method that is gaining popularity is UV-photochemical vapor generation (UV-PVG) atomic spectroscopy because it does not require sodium borohydride. In addition, this method of vapor generation is environmentally friendly. This work compares the Figures of Merit and other aspects of chemical and UV-PVG of Cd volatile species. Chemical hydride generation (CHG) was found to give lower limits of detection (LOD) and limits of quantification (LOQ) and a higher sensitivity. Both methods had different linear dynamic ranges. UV-PVG was found to give more repeatable results than CHG. In the next step, reaction modifiers were added to UV-PVG Cd(II) standards. The addition of Fe(II) improved the LOD, LOQ, sensitivity, linear dynamic range, and repeatability. Then, the volatile compound generation efficiency of UV-PVG was determined. Six solutions were analyzed, 0.5 and 1.0 ppm Cd(II) and 0.1, 0.2, 0.5, and 1.0 ppm Cd(II) with 100 ppm Fe(II). All solutions gave statistical zeros as a percent generation efficiency except the 0.1 and 0.5 ppm Cd(II) and 100 ppm Fe(II) standards gave a generation efficiency of 5.2% ± 3% and 1.4% ± 1%, respectively, with a 95% confidence interval.

Comparison of UV-photochemical vapor generation and chemical hydride generation for Cd(II) determination

2019 Spring National Meeting

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