Total Reflection X-Ray Fluorescence (TXRF) is a highly sensitive and selective method for trace metal detection. In this research, a method for potentially lowering the limit of detection and increasing oxidation state selectivity is developed using functionalized sol-gel films to concentrate metal ions on TXRF substrates. Sol-gel monoliths were formed using pyridine precursors to allow for selective binding of Cr(VI). Varying methods were explored for producing the sol-gel targets, focusing primarily on detecting Cr(VI) using internal standards in monoliths for indirect detection and films for direct analysis. Attempts at building a linear calibration mixing aqueous Yttrium and sol-gel monolith powders were ultimately unsuccessful, and instead, TiO<sub>2</sub> powder was incorporated into the sol-gel matrix as the internal standard. Limits of detection for typical solution based and sol-gel target based measurements are compared. The specificity of the method is also shown through detection of only Cr(VI) binding to the sol-gels when exposed to solutions also containing Cr(III) species. Modification of the sol-gel precursors used in this method make it possible to analyze other trace metals with a similar approach.

Development of metal ion specific sol-gel targets for trace metal total reflection X-ray fluorescence analysis

255th National Meeting (2018)

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