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.