The First Effective Method of Analysis for the Development of Ionochromic Azo Dyes for Aqueous Halide Detection

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Date

2012-06

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The Ohio State University

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Abstract

The environmental, industrial, and biological presence of halides requires versatile and sensitive detection methods. Targeting the development of a colorimetric indicator for anion detection requires probing the response to proton concentration, activity, solvent, and other anions. While current research recognizes the variable effects, standard methods to quantize these variables do not exist. The standard methods developed were used in a survey of the colorimetric properties of commercially-available azo dyes conducted in the presence of halides to target structural features for a halide indicator independent of pH effects. Sudan Black B revealed unique spectral shifts with quantitative additions of bromide independent of solution pH. Coupled with molecular modeling studies, imperative structural and electronic features critical for anion sensitivity are under continual investigation. Specifically, analogs of Sudan Black B were synthesized in efforts to optimize solubility and structural simplicity, and these analogs exhibited bromide sensitivity in acid aqueous medium and have been further tested. Ultimately, with the development of a halide selective indicator for aqueous solutions halide concentrations could be measured with extreme accuracy and precision at a much lower cost. This method of detection could also be applied to similar anions that present analogous detection difficulties in aqueous solution. The flexibility of a molecular indicator allows for detection in a variety of environments including human cells, more specifically measuring halide gradients.

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First Place Denman Undergraduate Research Forum
Best Poster Award Natural and Mathematical Sciences Forum

Keywords

Anion, Detection, Aqueous, Chemistry, Halide

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