Optimization of dispersive liquid–liquid microextraction of Co(II) and Fe(III) as their oxinate chelates and analysis by HPLC: Application for the simultaneous determination of Co(II) and Fe(III) in water samples

Abstract

In this study, dispersive liquid-liquid microextraction method was used for the preconcentration and simultaneous determination of Co(II) and Fe(III) in water samples as their oxinate chelates. In dispersive liquid-liquid microextraction process, methanol and chloroform were used as disperser and extracting solvents, respectively, and the ligand 8-hydroxy quinoline was used as a chelating agent for the extraction of Co(II) and Fe(III). HPLC was applied for the quantitation of the analytes after preconcentration. An experimental design, central composite design, coupled with response surface methodology was used for the optimization of the involved experimental parameters. In addition, the effect of various experimental parameters in the extraction was investigated using one variable at a time method. The calibration graphs were linear in the range of 20-4000 mg/L with the LODs of 3 mg/L for both analytes. The RSDs for six replicate measurements of 500 mg/L of Co 21 and Fe 31 were 3.3 and 4.1%, respectively.

Determination of cobalt, nickel and iron at trace level in natural water samples by in-column chelation-reversed phase high-performance liquid chromatography

“…Figure 7 shows a chromatogram taken for BCR 715 wastewater-SRM, by the HPLC-DAD. (Zhang et al 2005;Chung and Chung 2003;Peng et al 2005;Zhu et al 2007;Arain et al 2009;Amoli et al 2006;Farajzadeh et al 2010;Cheng et al 2008) was shown in Table 3. The limit of detection (LOD) for Co(II) is better than those of the direct HPLC measurements reported in the previous similar papers, also better than those of a combination of preconcentration and HPLC, required laborious and complicated sample preparation steps.…”

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

“…A DLLME method was presented by Farajzadeh et al [177] for the preconcentration of cobalt and iron ions prior to their determination by HPLC-UV technique. HPLC is a simple and relatively cheap technique that is needed for the samples at microlitre volumes.…”

Distorted octahedral environments in tricarbonylrhenium(I) complexes of 5-[2-(2,4,6-trimethylphenyl)diazen-1-yl]quinolin-8-olate and 5,7-bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-olate

“…Quinolin-8-ol mostly binds to metal ions in a bidentate fashion (Bernhardt & Lawrance, 2004). It has attracted interest in industrial applications, showing potential as an extracting agent for metal ions in dilute solutions (Farajzadeh et al, 2009). The bidentate ligand quinolin-8-ol can complex to a variety of metal ions, either as a neutral molecule or, more commonly, as a deprotonated anion with the loss of the hydroxy H atom (Maiti et al, 2005;Colquhoun et al, 2002;Xiang et al, 2011).…”