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.