Simultaneous determination of water-soluble herbicides using hydrophilic interaction liquid chromatography–mass spectrometry

Purpose The analysis of water-soluble herbicides, including glyphosate (Glyp), glufosinate (Gluf), paraquat (PQ), and diquat (DQ), is time-consuming and expensive because they cannot be analyzed using general toxicological screening methods. Thus, this study aimed to develop a simple and rapid method to simultaneously analyze these compounds without any derivatization nor ion-pairing reagents. Methods The analytes were separated using hydrophilic interaction liquid chromatography and detected using tandem mass spectrometry. The developed method was applied to plant and biological samples assuming criminal damage and poisoning cases, respectively. Results All analytes were separated well and detected with good peak shapes. For plant samples, the herbicides were specifically detected from withered leaves using a simple extraction method. For biological samples, quantitative analysis was successfully validated, and the limit of quantification values of Glyp and Gluf were 0.2 µg/mL, and those of PQ and DQ were 1 ng/mL. Conclusion The developed method had sufficient performance for practical forensic applications including poisoning cases and malicious uses to damage commercial crops.