Speciation of arsenic in wastewater samples based on pyributicarbamate /ionic liquids by dispersive liquid-liquid microextraction

Abstract

A simple and applied method based on O-3-Tert-butylphenyl N-(6-methoxy-2-pyridyl)-N-methylthiocarbamate (Pyributicarbamate; TBMPMTC) was used for arsenic speciation (AsIII and AsV) in urine and water samples by dispersive liquid-liquid microextraction (DLLME) procedure. The concentrations of arsenic in the liquid phase were determined by hydride generation atomic absorption spectrometry in the presence of flame accessory (HG-AAS). By procedure, a mixture of ionic liquid (0.1 g, [APMIM][PF6]@[HMIM] [PF6]), acetone (0.2 mL) and pyributicarbamate was injected into wastewater sample containing arsenic (AsIII and AsV) ions, which were already extracted by pyributicarbamate at the optimized pH. The task-specific ionic liquid (TSIL) of 1-3-aminopropyl)-3-methyl-imidazoliumhexafluorophosphate [APMIM] [PF6] was chemically synthesized and used for increasing of As(V) extraction in the liquid phase. As(III) was extracted based on the sulfur bond of pyributicarbamate at pH=5.3. As (V) can be extracted by amine group of TBMPMTC and [APMIM][PF6] at pH=3.0 (As(V)---:NH2). The influence of parameters such as, pH, amount of ionic liquid, and ligand was studied. Based on results, the LOD, enhancement factor (EF) and linear range (LR) were obtained 3.2 ngL-1, 9.85 and 0.01-1.2 μg L−1, respectively. The procedure validated by certified reference material (CRM).