Multiresidue analysis of pesticides in vegetables and fruits using a high capacity absorbent polymer for water

A single extraction and a single clean-up procedure was developed for multi -residue analysis of pesticides in non-fatty vegetables and fruits. The met hod involves the use of a high capacity absorbent polymer for water as a dr ying agent in extraction from wet food samples and of a graphitized carbon column for clean-up. A homogeneously chopped food sample (20 g) and polymer (3 g) were mixed to absorb water from the sample and then 10 min later the mixture was vigorously extracted with ethyl acetate (100 ml). The extract (50 ml), separated by filtration, was loaded on a graphitized carbon column without concentration. Additional ethyl acetate (50 ml) was also eluted an d both eluates were concentrated to 5 ml for analysis. The procedure for sa mple preparation was completed within 2 h. In a recovery test, 107 pesticid es were spiked and average recoveries were more than 80% from asparagus, or ange, potato and strawberry. Most pesticides were recovered in the range 70 -120% with usually less than a 10% RSD for six experiments. The results ind icated that a single extraction with ethyl acetate in the presence of polym er can be applied to the monitoring of pesticide residues in foods.