Combinação de processamentos matemáticos em dados voltamétricos: aplicação na eletroanálise de amostras socioambientais e determinação simultânea de antibióticos

Abstract

In this study, is presented an alternative electroanalytical method for the simultaneous determination of three fluoroquinolones in tap water samples. The procedure consists in the combination of low-density solvent liquid-liquid microextraction (MELL) assisted by ultrasound and the mathematical procedure based on second derivative. The procedure for the sample preparation via MELL allowed to extract and isolate selectively the fluoroquinolones (FQs), levofloxacin (LEVO), norfloxacin (NOR) and danofloxacin (DANO) as well as preconcentrate with a high enrichment factor (about 80 times). After extraction, the residues containing the analytes were redissolved in the electrolyte support and, portions containing microdrops, were detected directly (droplet-based) on the surface of the carbon nanofiber-modified screen-printed electrodes. The mathematical process was performed with correction of the baseline before and after the application of the second derivative of the voltammetric signals, allowing the separation of partially overlapping peaks and simultaneous detection. Finally, the combination of microextraction procedure and mathematical processing allowed application of target methodology for analysis of tap water samples to simultaneously determine the three FQs at trace levels and with a high recovery factor (values close to 100%).