SENSITIVITY, SPECIFICITY AND PREDICTIVE VALUE FOR THE ANALYSIS OF BENOMYL, AS CARBENDAZIM, ON FIELD-TREATED STRAWBERRIES USING DIFFERENT ENZYME-LINKED-IMMUNOSORBENT-ASSAY TEST KITS

The primary objective of this study was to evaluate the feasibility of enzyme linked immunosorbent assay (ELISA) for the determination of be nomyl in field-treated samples, as part of a multi-residue screen for pesticides. The rate of false positive and negative results using ELIS A as part of a monitoring program is a primary concern in determining its suitability as a screening tool. Sensitivity and specificity of EL ISA for benomyl residues in field-treated strawberries was determined using two different immunosorbent assays and the results compared to H PLC. The relative precision and agreement in quantitation for the thre e analyses was also examined. The Ohmicron Benomyl/Carbendazim Rapid A ssay established sensitivity and specificity Values of 100%, as did th e HPLC methods. The Millipore Benomyl/Carbendazim test kit had sensiti vity and specificity values of 93.3% and 51.9%, respectively, This was optimized to 86.6% and 94.2% by raising the minimum reporting detecti on limit to 0.050 mu g/g. While precision for the ELISA test kits, usi ng strawberries, was not as good as the HPLC, the less extensive clean up involved with ELISA analysis resulted in comparable overall variati ons. Agreement of quantitation for the three tests was significantly d ifferent. The sensitivity and specificity results obtained from the Oh micron Rapid Assay, after clean up with the Ohmicron Food Prep Kit, su pported its use as a potential screening toot for benomyl as carbendaz im. It is less labour intensive than HPLC methods acid provides a rela tively quick screen for benzimidazole compounds in general. Given unce rtainty of quantitation obtained from some matrices however, confirmat ion of positive results using HPLC is still highly recommended.