Simultaneous determination of morphine, caffeine, and paracetamol in the urine of addicts by HPTLC and HPLC

A simple high-performance thin-layer chromatographic (HPTLC) method is described for the identification and semi-quantitative determination of morphine, caffeine, and paracetamol in urine. The results obtained were further confirmed and quantified by high-performance liquid chromatography (HPLC), All the urine samples were first screened by use of the enzyme-multiplied immunoassay technique (EMIT), positive samples were then hydrolyzed, extracted, and analyzed by HPTLC and HPLC, HPTLC was performed on silica gel 60 F-254 plates with ethyl acetate-methanol-ammonia, 17 + 2 + 1 (nu/nu) as mobile phase. The developed plates were viewed in a UV cabinet at lambda = 254 nm and photographed. The concentrations of these drugs found in the urine of addicts by use of this method were in the ranges 0.1-4 mu g mL(-1) for morphine and caffeine and 0.1-6 mu g mL(-1) for paracetamol, HPTLC detection limits were 0.5 mu g for morphine and 0.2 mu g for caffeine and paracetamol. HPLC analysis of these drugs was per formed on a LiChrospher 100 RP-18 column with potassium dihydrogen phosphate (0.05 M) buffer-acetonitrile, 80:20 (nu/nu) as mobile phase, methyl dopa as internal standard, and UV detection at lambda = 280 nm, Calibration curves were linear and the HPLC detection limits were 20 ng mL(-1) for morphine, 5 ng mL(-1) for caffeine, and 10 ng mL(-1) for paracetamol. Detection of the drugs in the urine confirmed the abuse of brown sugar seized from the addicts.