The transport and fate of glyphosate [<i>N</i>-(phosphonomethyl)glycine], a herbicide used to control weeds in agricultural and urban areas, in surface water is poorly understood. Routine monitoring of glyphosate and its degradation product [aminomethylphosphonic acid (AMPA)] in surface waters can be cost prohibitive in terms of the analytical technique selected (e.g., LC-MS/MS), sample preparation, and number of samples to be tested. This project describes a study towards a cost-effective method that utilizes flow-injection analysis (FIA) and the phosphorus containing portion of glyphosate and AMPA molecules. Orthophosphate can be generated from glyphosate and AMPA under acidic and oxidizing conditions. This study explores varying the digestion method with different acids, acid concentrations, and oxidizing environments (e.g., UV light) to selectively decompose glyphosate and AMPA into orthophosphate. The produced orthophosphate is then quantified by forming the antimony-phospho-molybdate complex for UV-Vis spectrophotometric detection (880 nm). Optimized reaction conditions for selective digestion of glyphosate and AMPA to orthophosphate are presented.

Study towards the selective digestion of glyphosate in surface water

249th National Meeting (2015)

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