Liquid‐liquid Extraction Coupled to Batch Injection Analysis for Electroanalysis of Levofloxacin at Low Concentration Level

This work presents the integration between phase-separation by magnetic-stirring salt-induced high-temperature liquid-liquid extraction (PS-MSSI-HT-LLE) and batch injection analysis with amperometric detection (BIA-AD) as an alternative strategy for pre-concentration of analytes before hydrodynamic electroanalysis. To demonstrate the performance of this analytical system, the emerging contaminant levofloxacin was quantified in tap, aquarium and lake water at low concentration level. In the optimized conditions, BIA-AD enabled fast (160 h−1) and reproducible results (RSD<2 %) and the PS-MSSI-HT-LLE allowed the detection of levofloxacin concentration levels not detected by direct electroanalysis (70 and 80 nmol L−1) corresponding to 100-folds enrichment factors. The performance of proposed method was evaluated by addition-recovery test and was obtained satisfactory recovery values (between 70 and 96 %). Moreover, PS-MSSI-HT-LLE allows the pre-concentration of many samples simultaneously, which is advantageous over pre-concentration on working electrode surface (stripping methods).