Flow injection hydride generation atomic absorption spectrometry

• Main Author: Ellis, Robert Ian
• Language: ENG
• Published: ScholarWorks@UMass Amherst 1998
• Subjects: Analytical chemistry
• Online Access: https://scholarworks.umass.edu/dissertations/AAI9823732

Flow injection hydride generation atomic absorption spectrometry is the practice of derivatizing the analyte to the volatile hydride by flow injection and introducing it to the spectrometer in the gas phase. Although hydride generation is well developed, there are still aspects and nuances which require investigation to improve the understanding of this method of sample introduction. The suggestion that the addition of various surfactants to the reagents in the hydride forming reaction has beneficial effects has been investigated. Although, in previous reports, an increase in sensitivity had been reported in the presence of surfactants, such an improvement was not observed for the flow injection procedure used in the work described in this dissertation. The effect of dissolved salts on the hydride forming reaction has been investigated. An increase in sensitivity in the presence of high concentrations of dissolved salts has been observed. This has been attributed to an increase in the proportion of the volatile hydride which is removed from the reagents in the on-line procedure. In the hydride trapping procedure, the hydrides are trapped on the interior of an electrothermal atomizer prior to atomization. Although previous reports have indicated that one may improve the limit of detection simply by increasing sample size, a practical and theoretical investigation concluded that the relationship is not linear, and that the limit of detection is limited by impurities in the reagents. Methods for the determination of lead by hydride generation with quartz tube and electrothermal atomization have been developed. The use of an oxidizing agent makes this method a little more complicated than for other elements. The determination of total selenium in urine has been attempted using an on-line digestion procedure in which bromine is generated in-situ. Whilst this method has been demonstrated to be effective in an off-line procedure, the development of a method with on-line digestion was not successful. The use of an alternative oxidizing agent and energy supply mechanism would be appear to be necessary.