Validação de um método prático para determinação de níveis de amoxicilina em águas naturais por CLAE-UV e sua aplicação na qualidade ambiental Validation of a practical method for determination of amoxicillin contents in natural waters by means of HPLC-UV and its application in the environmental quality

Amoxicillin is a synthetic penicillin used in the hospital, residential and veterinary surroundings. The indiscriminate use of such medication may cause social and environmental damages. This study aims at determining the amoxicillin contents in water of two rivers located in State of Bahia, the Agua Fria and Verruga rivers. An analytical method was developed, optimized and validated for determining the amoxicillin residue, by using the high performance liquid chromatography coupled with UV-Visible detector (HPLC-UV). The study was performed according to the chromatographic parameters validation. Considering that the maximum acceptable values of amoxicillin for drinking water were nonexistent, the found results might be considered as an indicator of contamination by this substance. The occurrence of this antibiotic in the two rivers analyzed in this study indicated a heavy contamination in the urban areas where the increased surface water runoffs occur; and their concentrations were higher than 11 mg.L -1 . The validation parameters indicated that the method showed the capacity for detecting low values of quantification limits (2.7 mg.L -1 ) and of detection (0.7 mg.L -1 ), good precision (DSR 7 %) and accuracy (96.75 %), thus it turned to be an important tool for assessing amoxicillin contents.