Concentration of the Organophosphorus Pesticides: Fenchlorphos, Crufomate and Nogos in Water By Using Amberlite XAD-2


Abstract The pollutants organophosphorus pesticides : fenchlorphos, crufomate and nogos in water are concentrated on a column of a macro reticular amberlite XAD-2 resin adsorbent and recovered by elution with acetonitrile, methanol and chloroform. The distribution coefficient, Kd for chromatographic separation ( adsorption and desorption }has been calculated for each pesticide with each solvent. This resin proved to be rapid and efficient for adsorption of these pesticides from water samples and acetonitrile or methanol are the best solvent for pesticides desorption due to powerful polarity of solvent as well as dielectric constant compared with chloroform . We suggest simple relationship between the column void volume and volume of organic solvent needed to elute each pesticides quantitatively ; it has found that the best desorption obtained with optimal volume of acetonitrile or methanol equals to three to four times that of the adsorption column void volume, when the elution solvent allow to stand for one hour at a flow rate 1 ml./ min. . The 30% Breakthrough capacity was calculated to check elute recovery for fenchlorphos, crufomate and nogos and found to be equals to 3330, 7030 and 19100 µg pesticides/ ml XAD-2 resin 3.45, 7.52 and 20.4 µg (pesticides) /mg XAD-2 resin respectively, which are inversely proportional to the molecular weight of these pesticides. Concentration Factor ( CF ) is calculated and found to ranging from 1500 to 3000 which proved the accuracy of this method for being present at trace concentration of these pesticides in water samples.