Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

Abstract

Abstract:A rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C 6 py][PF 6 ] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C 6 py][PF 6 ]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L −1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L −1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2−166 µg L −1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

Chelate Extraction of Metals into Ionic Liquids

“…Recently, Molaakbari et al [98] applied USA-DLLME to the extraction preconcentration of Rh 3+ with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP, 19). In contrast, application of DLLME by disperser solvent to IL chelate extraction has been studied in depth by Abdolmohammad-Zadeh et al [99][100][101], Shemirani et al…”

Separation and Preconcentration by Dispersive Liquid–Liquid Microextraction Procedure: Recent Applications

“…Waters [139] Separation and Preconcentration by DLLME 667 Water and milk samples [171] As, Sb Water and food samples [173] Separation and Preconcentration by DLLME 669 Table 2 continued Analyte Disperser solvent volume Water and biological samples [188] both detection techniques, which thus enables the application of the developed method in two ranges differing from one another by three orders of magnitude. More recently, DLLME was used by De La Calle et al [134] to preconcentrate the ion pair formed between AuCl 4 -and [CH 3 (CH 2 ) 3 ] 4 N ?…”

“…The attempt of the investigation group of Abdolmohammad-Zadeh was focused on the application of pyridinium ILs in DLLME of metal ions, cobalt [139] and zinc [171]. In this way, 1-hexylpyridinium hexafluorophosphate was employed as an extractant solvent considering its good performance, water-immiscibility, high hydrophobicity, and quite viscosity.…”

A study on phenol migration by coupling the liquid membrane in the ionic liquid

“…The chemical reaction at the interface is in a continuous and stable state to derive an osmotic coefficient equation of the metallic ion in the dispersion supported liquid membrane as shown [23,24,25]:…”