Solid-phase extraction of phosphorous-containing amino acid herbicides from biological specimens with a zirconia-coated silica cartridge

•A cleanup method for glyphosate, glufosinate and bialaphos is presented.•A zirconia-coated silica cartridge was used for solid phase extraction.•The present method was rapid and highly selective.•The method was validated and the results were sufficiently good.•The calibration range covers almost all the reported poisoning cases.

We report a rapid solid-phase extraction method for glyphosate (Glyp), glufosinate (Gluf), and bialaphos (Bial) using a zirconia-coated silica cartridge, which interacts specifically with phosphorous-containing amino acid herbicides (PAAHs). We extracted PAAHs from serum and urine samples. The PAAHs were derivatized with trimethyl orthoacetate-acetic acid and analyzed by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC–MS/MS). The intra-day and inter-day accuracy was within ±13% RE, the intra-day and inter-day precision was less than 12% RSD, and the total recovery was more than 60% for Glyp and more than 80% for Gluf and Bial. The linearity ranges of the calibration curves of the serum samples were 0.2–10,000 μg/mL for Glyp, 0.1–1000 μg/L for Gluf, and 0.5–1000 μg/L for Bial; and those of the urine samples were 0.4–20,000 μg/L for Glyp, 0.2–2000 μg/L for Gluf, and 0.1–2000 μg/L for Bial. This range covers almost all the reported poisoning cases involving these compounds, from very mild to fatal cases. The present paper offers a universal cleanup method for PAAHs in serum and urine samples for clinical and forensic analysis.