Sensitive analysis of glyphosate and ampa without the need for derivitisation by ion chromatography tandem mass spectrometry in environmental water samples

Importance of the Topic

Glyphosate and its primary metabolite AMPA are pervasive in agricultural runoff and wastewater, raising environmental and public health concerns due to their persistence and potential toxicity. Reliable detection in water matrices is vital for monitoring pollution, guiding regulatory compliance, and informing remediation strategies.

Objectives and Study Overview

This study aimed to develop a streamlined high-performance ion chromatography tandem mass spectrometry method (IC-MS/MS) for direct quantification of glyphosate and AMPA in surface and effluent water samples without requiring chemical derivatization. The approach emphasizes simplicity, sensitivity, and robustness under high ionic strength conditions.

Methodology and Instrumentation

The analytical workflow combines anion exchange chromatography with on-line electrolytic generation of a KOH gradient, followed by self-regenerating anion suppression prior to detection. Direct injection of unfiltered water samples is enabled by a high-capacity Thermo Fisher Scientific Dionex IonPac AG24+AS24 column operated at 0.25 mL/min and 30 °C. The eluate is desalinated using an ASRS®300 suppressor at 25 mA before entering a Thermo Scientific Vantage triple quadrupole mass spectrometer in negative SRM mode. Key SRM transitions selected were 168→79 and 168→63 for glyphosate, and 110→79 and 110→63 for AMPA. Data acquisition and processing were performed using Chromeleon and Xcalibur software.

Main Results and Discussion

The method achieved linear calibration from 1 to 50 µg/L for both analytes with coefficient of determination exceeding 0.99. Isocratic retention tests ensured baseline separation from common anions (chloride, sulfate, nitrate, etc.) and demonstrated long-term stability. Spiking experiments in surface water at 2 µg/L yielded clear SRM signals despite being below the conductivity detector’s limit, confirming superior MS sensitivity. Product ion spectra validated the selected transitions and minimized interferences from matrix ions.

Benefits and Practical Applications

The proposed IC-MS/MS protocol offers several advantages: elimination of laborious derivatization steps, direct analysis of high ionic strength samples, reduced sample preparation time, and reliable quantification at low µg/L levels. It is well suited for routine environmental monitoring, wastewater treatment evaluation, and regulatory compliance testing.

Future Trends and Potential Applications

Further enhancements may target lower detection limits suitable for drinking water analysis and expansion to additional glyphosate metabolites. Integration with high-resolution mass spectrometry and automated sample handling could broaden applications to comprehensive pesticide screening and real-time environmental surveillance.

Conclusion

The developed IC-MS/MS method provides a straightforward, robust, and sensitive platform for analyzing glyphosate and AMPA in complex water matrices. Its compatibility with direct injection and mass spectrometric detection makes it an efficient tool for environmental laboratories seeking rapid and accurate pesticide quantification.

Reference

• You J, Koropchak JA. Condensation nucleation light scattering detection with ion chromatography for direct determination of glyphosate and its metabolite in water. J Chromatogr. 2003;989:231–238.
• Yang C, Henday S, Wang L, Schnute B. Analysis of Glyphosate and AMPA in Environmental Water by Ion Chromatography Electrospray Tandem Mass Spectrometry (IC-ESI-MS/MS). Application Note 491. Thermo Fisher Scientific Inc.; 2010.