An Improved Extraction Method for the Quantitative Analysis of Pesticides in Water

A new method for the enrichment of pesticide residues in water by liquid/liquid extraction with n-pentane in a light phase rotation perforator according to Ludwig is described. Altogether 44 compounds (chloropesticides, urones, triazines, phosphoric acid esters and others) were analyzed at given concentrations by gas chromatography. Four phosphoric acid esters and two other compounds showed insufficient recovery rates between 50% and less than 10% due to their decomposibility in aqueous solutions. All other analyzed substances showed very good average recoveries of 80% to 115%. Detection limits ranged from 10 to 100 ng/1, dependent on the detectors (ECD. PND) and enrichment factor (1000 and 2000, respectively). The applicability of this enrichment method to residue analysis of pesticides in surface water and groundwater is demonstrated and its practicability is discussed.