Liquid Chromatographic Determination of Glyphosate Technical and Its Formulation: Collaborative Study

Abstract

An HPLC method for the determination of glyphosate in formulation and technical samples has been subjected to a collaborative study with 12 laboratories participating. This method requires no sample pretreatment. Samples were dissolved in mobile phase, injected directly using a fixed-volume loop, and quantitated by an external standard technique. Compounds were separated on a strong anion exchange column with a water-methanol (96 + 4) mobile phase that was 0.0062M in KH2P04 and adjusted to pH 1.9 with 85% H3PO4, and detected with a variable wavelength UV detector at 195 nm. Calculations were made using peak areas. The collaborative study involved 3 pairs of matched samples with single determinations on each sample: Roundup herbicide, a technical intermediate, and technical glyphosate. The coefficients of variation for the 3 pairs were 1.70, 0.88, and 0.90%, respectively. The method has been adopted official first action.

Glyphosate Uptake by Suspension-Cultured Potato (Solanum tuberosumandS. brevidens) Cells

“…Grass control was higher from postemergence diclofop {(±)-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid}, fluazifop, and sethoxydim when applied to plants grown in soil with adequate moisture compared to plants grown with a moisture stress (7,10,14,15). Fluazifop at 0.56 kg/ha provided 20% higher control of quackgrass [Agro pyron repens (L.) Beauv.…”

“…The two aqueous fractions were combined, dried 4 , soiubilized in the high-performance liquid chromatography (HPLC) mobile phase [water and methanol mixture (96:4, v/v) containing 6.2 mM KH 2 P0 4 , and adjusted to pH 1.9 with an H 3 P0 4 and water mixture (85:15, v/v)] and centri fuged at 14000 g for 10 min. The supernatant was assayed for the presence of glyphosate metabolites by separation of radioactive compounds by HPLC (6,7). A 20-//1 aliquot of the supernatant was injected onto an anion exchange column 5 (4 mm i.d.…”