DETERMINATION OF CARBAMATE PESTICIDES IN FRUITS AND VEGETABLES BY MEANS OF HIGH-PRESSURE LIQUID-CHROMATOGRAPHY

It is shown that carbamate pesticides can be determined at the ppm level in different kinds of fruits and vegetables using high pressure liquid chromatography. The lower detection limit corresponding to a signal to noise ratio of three is between 0,025 and 0,25 ppm depending on the type of carbamate and plant material. In all cases it is below the maximum permissible value for pesticide residues. Due to the high separating power of high pressure liquid chromatography a simple sample pretreatment procedure can be used. The carbamates are extracted from the biological sample by dichloromethane and injected directly into the liquid chromatograph after replacing the extraction solvent by the mobile phase. In many cases a definite identification and quantitation of the carbamate is possible with a single chromatographic column. Some plants with a more complex matrix require a two-column operation in which the effluent fraction of the first column containing the pesticide is transferred by column switching to a second column in order to achieve a complete separation. The improved resolution in the two-column operation is caused by the relative enrichment effect of the fractionation and the increased column length. © 1979 J. F. Bergmann Verlag.