Determination of organochlorine pesticides and chlorobenzenes in fruit andvegetables using subcritical water extraction combined with sorptive enrichment and CGC-MS

A scheme has been developed for the determination of hexachlorocyclohexanes , DDX compounds and chlorobenzenes in fruit and vegetable samples (strawber ries, apples, kohlrabi, lettuce and tomatoes). The method is based on the a ccelerated solvent extraction (ASE) with water or water-acetone mixtures fo llowed by solid-phase microextraction (SPME) and stir bar sorptive extracti on (SBSE), and subsequent thermodesorption-CGC-MS. Using spiked water and s trawberry samples, important SPME and SBSE as well as ASE parameters were o ptimized. The ASE-SPME and ASE-SBSE procedures developed and optimized for the matrix strawberry could be applied successfully to other fruits and veg etables (apples, kohlrabi, lettuce and tomatoes). Both procedures were appl ied to the different matrices and evaluated. The relative standard deviatio ns (n = 5) for the analytes in different plant materials were in the range of 4 to 31% for both procedures. For the ASE-SPME procedure detection limit s (LOD) between < 0.5 and 6 <mu>g kg(-1) were achieved except for the DDX c ompounds (up to 40 mug kg(-1)). Using the ASE-SBSE, the LOD values for most of the analytes could be significantly improved. These procedures were app lied to the determination of chlorobenzenes, HCH isomers and DDX compounds in strawberry, apple, kohlrabi, lettuce and tomato samples taken from 12 al lotment gardens in a potentially polluted region of East Germany.