[Simultaneous determination of josamycin, theophylline and paracetamol in pharmaceutical waste water by high performance liquid chromatography].

A high performance liquid chromatographic (HPLC) method was established for the simultaneous determination of three main pollutants (josamycin, theophylline and paracetamol) in pharmaceutical waste water. The three drug residues were concentrated with a SepPak C18 solid-phase extracted column, and eluted with methanol. The HPLC separation was performed on a Hypersil ODS column (200 mm x 4.6 mm i.d.) with a gradient eluting system of 0.025 mol/LKH2PO4-H3PO4 (pH 2.75)-methanol. The detection wavelengths were 230 nm for josamycin, 272 nm for theophylline, and 243 nm for paracetamol. The linear ranges of the drugs were 0.1-100 mg/L with correlation coefficients between 0.9993 and 0.9995. The recoveries were more than 93%, and relative standard deviations (n = 6) were less than 2.1%. The detection limits (S/N = 3) were less than 1.0 microg/L.