Determinação de Contaminantes Traços Usando Microextração Líquido-Líquido com Análise por Injeção em Batelada

Liquid-liquid microextraction (LLME) has been considerate a miniaturized extraction technique that attends the principles of green chemistry, since it enables the preconcentration of analytes from extremely dilute samples without using toxic organic solvents.Also, LLME requires a negligible volume of the sample and extractor solvent, presents lowcost,time and generation of residues [1, 2]. Tube-less Flow-Injection Analysis or Batch Injection Analysis (BIA) [3] also fulfils some green principles as low: energy requirements (portable systempowered by battery), sample (and reagents) consumption and waste generation. This work proposes the combination ofmagnetic-stirring salt-induced high-temperature liquid-liquid microextraction (PS-MSSI-HT-LLME) and batch injection analysis with amperometric detection (BIA-AD) to fast and clean determination of contaminants at trace levels. To demonstrate the performance ofthe proposed system, the emerging pollutant levofloxacin (LEVO) was quantified in tap water at low concentration levels.The LEVO solutions were injectedby an electronic micropipette just above of the Boron-Doped Diamond (BDD) working electrode (d 2 mm) placed in a homemade BIA cell(wall jet configuration), while AD was performed applying +1.3 V in BDD (vs Ag/AgCl/KClsat.).After optimization conditions of pre-concentration by PS-MSSI-HT-LLME (type and salt concentration, extractor solvent, temperature and stirring rate of extraction)and electrochemical detection by BIA-AD (pH, dispensing rate, injection volume and stirring rate),the proposed system presentedfast analysis (160 h‒1)and high precision (RSD < 2 %), as well the determination of LEVO at very low levels (80 nmol L‒1) with an enrichment factor of around 100 times and goodaccuracy without matrix interferences(recovery of 97 %). Moreover, the hyphenation of PS-MSSI-HT-LLME and BIA-AD allowedthe processing of severalsamples at the same time(anadvantage over pre-concentration in electrode surfaceperformedin the stripping methods) in a simple and compact system.