Determination of sulfonamides and trimethoprim in spiked water samples by solid-phase extraction and thin-layer chromatography

This paper describes a method for separation and quantification of a mixture of antibiotics extracted from spiked water samples. The method involves SPE of the analytes from water then analysis of the extract by TLC. Excellent separation of sulfadimidine, sulfadiazine, sulfaguanidine, and trimethoprim (TMP) was achieved by HPTLC on silica gel F-254 plates with chloroform- methanol, 89 + 11, as mobile phase. Videodensitometric quantification was validated for linearity, precision, limit of detection, and limit of quantification. Limit of detection (LOD) was 0.05 mu g per spot for sulfadimidine, sulfadiazine, and sulfaguanidine, and 0.1 mu g per spot for TMP. Limit of quantification(LOQ) was 0.1 mu g per spot for sulfadimidine, sulfadiazine, and sulfaguanidine, and 0.2 mu g per spot for TMP. The TLC method was tested on extracts obtained, by use of solid-phase extraction, from spiked water samples. The best recovery of these antibiotics was achieved by use of HLB cartridges and elution with acetonitrile. Apparent recoveries were 87.1 +/- 8.4 for sulfadiazine, 93.1 +/- 6.4 for sulfadimidine, 16.1 +/- 7.2 for sulfaguanidine, and 108.7 +/- 23.7 for trimethoprim.