We developed and validated an assay for determination of glyphosate (GLYP) and glufosinate (GLUF) in human serum. Serum samples were extracted by using a MonoSpin® TiO column and analyzed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). MonoSpin® TiO tends to specifically bind to phosphate groups. The assay was linear over a concentration range of 1–250 μg/mL. The recoveries for the 2 compounds were 1.6%–2.3%. The intra- and inter-day variations were <15%. Precision and accuracy were 5.6%–12.7% and 97.0%–103.9%, respectively. The validated method was applied to quantify the GLYP and GLUF content in the serum of GLYP and GLUF-poisoned patients. In conclusion, the method was successfully applied for accurate determination of GLYP and GLUF in serum obtained from patients with GLYP and GLUF poisoning.
A novel method coupling spin column extraction with high-performance liquid chromatography–mass spectrometry was developed for simultaneous extraction of β-blockers and calcium channel blockers from human serum. Sample loading, washing, and elution were accomplished via centrifugation of the column, in which mixed-mode monolithic silica bonded to a C18 reversed phase, and a cation-exchange phase was packed in a spin column. The serum sample (0.2 mL) pH was adjusted to 3 and the analytes adsorbed onto the column were eluted with 0.1 mL MeOH containing 2% NH3. The recoveries of the tested drugs were 76–108%. A linear curve was observed up to a concentration of 500 ng/mL of the target drugs in serum (r2 > 0.996). The intra-day relative standard deviations at three different concentrations were 0.6–9.6%. The limits of detection were 2 ng/mL. The proposed method was successfully applied to clinical and forensic cases.