Application of a triasulfuron enzyme immunoassay to the analysis of incurred residues in soil and water samples

Abstract

An enzyme immunoassay (EIA) for triasulfuron produced by Millipore, Inc., was incorporated into an analytical method for the analysis of incurred residues in soil and water samples. All samples used in the validation study were obtained from triasulfuron field studies and were previously analyzed by either high-performance liquid chromatography (HPLC) or HPLC with mass spectrometric detection (LC/MS). Water samples were analyzed directly without any sample preparation. Soil samples were extracted in a methanol/phosphate buffer solvent system by vortex mixing and sonication. The soil extract was cleaned up by solid phase extraction (SPE). Residues in the SPE eluate were brought up in Tris-HCl buffer and analyzed directly in the buffer solution. Immunoassay results compared favorably with HPLC (r = 0.93, water samples) and LC/MS data (r = 0.88, soil samples). The immunoassay method has a lower limit of detection at 0.05 ppb than either of instrumental methods. The limits of quantitation for the EIA in water and soil are 0.05 and 0.10 ppb, respectively.