The direct quantitation of glyphosate, a non-selective herbicide, and its main degradation product aminomethylphosphonic acid (AMPA) in various raw agricultural commodities (RACs) has been complicated by the ionic nature of these analytes, the lack of sensitive and detectable structural moieties, and their propensity to interact strongly with stainless steel surfaces. Most analytical procedures involve derivatization and extensive sample cleanup. A simplified LC-MS/MS method has been developed that overcomes or minimizes many of these challenges while dramatically increasing sample preparation throughput. The optimization of sample homogenization was identified as a key component to enabling the scale-down of extraction and processing. The utilization of phosphoric acid as a sample extraction modifier was found to have supplemental benefits in minimizing the interactions with stainless steel surfaces that broaden peaks, increase tailing, and can affect injection carryover. This new methodology is capable of measuring underivatized glyphosate and AMPA down to 0.05 ppm in RAC samples.

High throughput analysis of glyphosate and aminomethylphosphonic acid in raw agricultural commodities

242nd National Meeting (2011)

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