Resumo:
Water and effluent contamination by drugs is a subject that has mobilized the entire scientific community in recent decades. The presence of several compounds in surface water, especially antibiotics such as ciprofloxacin (CIP), indicates the risk of continuous exposure to trace levels of this compound, which is related to the development of bacterial resistance. Ciprofloxacin is one of the most widely used antibiotics by the Brazilian population and is characterized as an emerging contaminant in several environmental compartments. However, studies conducted in the country on the presence of drugs in the environment are still scarce. In this context, this study developed an extraction (SPE) and chromatographic (HPLC-PDA) methodology to determine this agent in the surface water of the Joanes River, a water source responsible for part of the water supply of Salvador and the metropolitan region. Chemometric tools were used to assemble the solid phase extraction (SPE) method that applies an HLB cartridge and uses ethanol as an extracting solvent. For the analytical step, several factors were evaluated in order to improve the determination of ciprofloxacin by HPLC-PDA, with C18 column. The run performed in gradient mode, uses ethanol as an organic modifier of the mobile phase. The use of ethanol generated a response similar to acetonitrile and this modification favored the adaptation of the methodology to the principles of Green Analytical Chemistry. The method has a detection limit (LD) of 0.05 μg L-1 and a quantification limit (LQ) of 0.2 μg L-1. With an analytical curve constructed from 0.2 μg L-1 to 10 μg L-1, the recoveries of the standards prepared in the sample matrix were 90% to 102%, indicating good suitability of the method. To apply the method, 15 samples were collected along the Joanes River from August to October 2024. From the points collected, it was possible to detect the presence of CIP in 03 of them, with concentrations that indicate a potential ecological risk for the development of bacterial resistance and ecotoxicological effects. This study proposes the application of chromatography with a photodiode detector to map the contamination of rivers by emerging contaminants, such as ciprofloxacin, in order to guide control and monitoring actions. In general, the study on the presence of drugs as emerging contaminants helps in the assessment of the impacts that drugs can generate on the environment, contributing to awareness and improvement of water quality.
