Identification and determination of sulphamethazine and N4-acetylsulphamethazine in meat by high-performance liquid chromatography with photodiode-array detection.

Abstract A simpled and selective method for the determination of sulphamethazine (SMT) and its metabolite, N 4 -acetylsulphamethazine (N 4 -AcSMT), in meat by high-performance liquid chromatography (HPLC) with photodiode-array detection was developed. The drugs were extracted from meat with 0.2% metaphosphoric acid-methanol (6:4), followed by a Bond-Elut C 18 clean-up procedure. The HPLC separation was carried out on a Supersphere RP-18e column (125 × 4.0 mm I.D.) using 0.05 M sodium dihydrogenphosphate (pH 4.5)-acetonitrile (8:2) as the mobile phase at a flow-rate of 0.5 ml/min, and monitored with a photodiode-array detector. The recoveries of SMT and N 4 -AcSMT from meat fortified at 0.5 μg/g were 90.1–93.3 and 93.0–94.4%, respectively, with coefficients of variation of 1.9–3.2 and 1.5–2.7%. The limits of detection were 0.02 μg/g for each drug. SMT was found in ten samples of imported meat (12.5%) at levels ranging from 0.05 to 1.05 μg/g.