Determination of sulfonamides in animal tissues using cation exchange reversed phase sorbent for sample cleanup and HPLC-DAD for detection

摘要

A new extraction method for 12 sulfonamides (sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethizole, sulfadi-midine, sulfisoxazole, sulfamethoxazole, sulfatroxazole, sulfachlorpyrazine, sulfaphenazole and dapsone) in muscle, liver and kidney was developed. Fortified tissues of muscle, liver and kidney from bovine, pig and chicken were studied. A 10 g tissue and 10 ml acetonitrile were homogenised with an Ultra-Turrax. Next, the tissue was defatted with 5 ml n-hexane, centrifuged and filtered into flasks. Then the extracts were acidified with 10 ml hydrochloric acid and diluted with deionised water. Next, the samples were loaded on OASIS~(~R) MCX columns, which were conditioned with 5 ml methanol and 5 ml water. The columns were washed with 5 ml hydrochloric acid and 5 ml methanol. Then the samples were eluted with 5 ml ammonia solution/acetonitrile (v/v 1/19), allowed to dry under nitrogen and reconstituted in 200 μl acetonitrile/water-mixture (v/v 1/4). The analyses were carried out on HPLC-DAD. Mobile phase was 0.01 M ammonium acetate pH 4.6 (A) and acetonitrile (B). Chromatographic separation was obtained by gradient elution (5% B to 40% within 16 min, back to 5% in 1 min, equilibration for 3 min). The sulfonamides were detected at 260 nm and dapsone at 294 nm. The detection limits of the HPLC method were 1 ppb for all analytes.