HPLC method for determination of oximes HI-6 and trimedoxime in plasma

Abstract

A high-performance liquid chromatographic (HPLC) assay was developed to determine HI-6 and trimedoxime concentrations in small volumes of plasma. The HPLC system comprised a high-pressure pump (model 2150), a multiwavelenght detector (model 2140) set at 284 nm and 295 nm for detection of trimedoxime and HI-6, respectively, and a sample injector (Rheodyne, model 7125) with a 20 μL sample loop. A Superpac starter kit 5 μm ODS 2; 4 x 250 mm (Pharmacia LKB) stainless steel column was used. To plasma sample, 10 μL of 20% trichlorocetic acid, was added. From the supernatant, 20 μL was injected directly into HPLC. The solvent was 25% acetonitrile in 0.08 mol/L acetic acid (pH 3) containing 0.01 mol/L heptane-1-sulfonic acid (sodium salt) and 0.0025 mol/L tetramethylammonium chloride. The flow rate was 0.8 mL/min HI-6, and trimedoxime eluted at about 6.0 min and 8.0 min, respectively. The limit of sensitivity was 1.4 μmol/L of trimedoxime and 2.5 μmol/L of HI-6. Recovery rates were 99.02% in determination of HI-6 and 100.6% in determination of trimedoxime. Coefficients of variation for HI-6 and trimedoxime ranged from 1.4% to 8.2% and 0.9% to 3.4%, respectively. Our results indicate that the method is sensitive, accurate and precise.