COMPARISON OF SULFADIMETHOXINE RESIDUE ANALYSES IN SALMON MUSCLE USING HPLC AND CHARM-II TEST

Sulfadimethoxine (SDM) residues in chinook salmon muscle were measured by high-performance liquid chromatography (HPLC) and the Charm II tes t to evaluate the efficacy of the Charm test for the measurement of su lfonamide residues in fish muscle. Both HPLC and Charm analyses were p erformed in the presence of salmon tissue matrix for the purpose of ev aluating the results in field conditions. The sensitivity of the HPLC method was 0.05 mu g/g (0.05 ppm) for SDM, while the sensitivity of th e Charm II test was at least 0.01 ppm. SDM analysis from salmon fed Ro met-30(R) performed using the Charm assay gave consistently lower valu es compared to HPLC; however, good agreement was obtained between both methods (tau(2) = 0.944) over a concentration range of 0.1 to 13.0 pp m in muscle tissue. The large variation in SDM concentrations between fish sampled on common days suggests that a larger number of fish are required for more accurate risk assessment. In the current investigati on, the Charm II test was shown to be effective in measuring SDM in sa lmon muscle tissue for the large sample throughput common with antibio tic-screening strategies.