Development and Validation of Liquid Chromatography-Tandem Mass Spectrometry Methods for Determination of Beta-Lactams, Macrolides, Fluoroquinolones, Sulfonamides and Tetracyclines in Surface and Drinking Water from Rio de Janeiro, Brazil

Two analytical methods for determination of five antibiotics classes in surface water and drinking water samples were developed and validated based on solid phase extraction followed by high-performance liquid chromatography coupled to tandem mass spectrometry. Two distinct chromatographic gradients were used according to the polarity of the different pharmaceuticals. The methods were applied for the quantification of 46 analytes belonging to beta-lactams, macrolides, fluoroquinolones, sulfonamides and tetracyclines classes. Validation results showed recoveries above 75% for the studied analytes in water samples. The method limits of detection calculated for the surface water and drinking water samples were, respectively, from 1 to 12 ng L-1 and from 0.15 to 20 ng L-1. The method limit of quantification ranged from approximately 3 to 38 ng L-1 for surface water samples and from 0.5 to 64 ng L-1 for drinking water samples. The methods showed to be linear over the range of 25 to 1000 ng L-1 with coefficients of determination greater than 0.94. Amoxicillin, cephalexin and sulfamethoxazole as high as 105 ng L-1 were found in surface water and erythromycin, azithromycin and clarithromycin up to 35 ng L-1 could also be found in surface water. Clarithromycin, cefaclor, oxacillin, sulfamethoxazole and troleandomycin were detected in the lower range up to 10 ng L-1 in drinking water.