Simultaneous determination of carbamate pesticides in human serum and urine by automatic reversed-phase HPLC combined with on-line column enrichment

Carbamate pesticides (pirimicarb, PHC, bendiocarb, XMC, NAC, ethiofencarb, and MIPC) in human serum and urine were determined by an automatic on-line column-enrichment technique followed by reversed-phase high-performance liquid chromatography with photometric detection. After human serum was filtered through a membrane filter (0.45 μm pore size), an aliquot of 0.1 ml of the filtrate was diluted with water up to 1 ml. A solution of 0.8 ml was directly injected to an automatic HPLC without any pretreatment. Human urine was incubated with β-glucuronidase/arylsulfatase for 16 hours at 37°C. The resultant solution was then filtered through a membrane filter and the filtrate was analyzed by a similar manner as the serum. Carbamates in the sample solution were concentrated on a pre-conditioned ODS mini-column. After washing the mini-column with 10% methanol, they were separated by an ODS analytical column (Cosmosil 5 C₁₈-MS-II, 250 x 4.6 mm ID, 5°C) with an acetonitrile/water eluent (32:68, v/v) and detected at 220 nm. The presented HPLC method requires neither a manual procedure of solid-phase nor liquid-liquid extraction. Calibration curves for seven carbamates were linear over the range of 0.1-50 μg/ml in serum, and 1-50 μg/ml in urine. Recovery tests were carried out with human serum and urine. Recoveries of 25 and 2.5 μg in serum were 100 -103%, and those of urine were 98-104%. The relative standard deviations of the recoveries were less than 3%.