High-performance Liquid Chromatography/uv Detection for Determination of Glyphosate in Serum and Gastric Content

In Thailand, poisoning by glyphosate (GLYP)-containing the herbicide, Roundup®, has been increasing. A high-performance liquid chromatographic (HPLC) method with UV detector has been developed for quantitating glyphosate. The serum samples (0.2 mL) were precipitated with acetonitrile (0.2 mL), and the supernatant was then injected directly into the chromatographic system using a fi xed volume loop. The glyphosate was eluted on an adsorbosphere XL SAX 90A 10μ column (25 cm x 4.6 mm, I.D.). The mobile phase consisted of 0.8437 g of KH2PO4 in 960 mL of H2O and 40 mL of MeOH, and the pH was adjusted to 2.1 with 85% H3PO4. The peak area response, as measured by a UV detector, was quantitated by the external standard technique at 195 nm. The retention time of glyphosate was 7.3 min. The concentration was detected between 0.25-4.0 g/L. The limits of detection (LOD) and quantifi cation (LOQ) were 0.27 and 0.44 g/L, respectively. The mean recovery was 92.1% and the coeffi cients of variation (CV) ranged from 6.7-12.9%. This analytical method is simple, and therefore appropriate for forensic purposes. Two fatal cases of glyphosate poisoning are presented, with a lethal serum concentration of 0.57 and 3.05 g/L, respectively. Chiang Mai Medical Journal 2008;47(4):155-162.