Vortex-assisted low density solvent and surfactant based dispersive liquid–liquid microextraction for sensitive spectrophotometric determination of cobalt

Abstract

This study describes the development of vortex-assisted low density solvent and surfactant based dispersive liquid-liquid microextraction (VALS-DLLME) for Co(II) prior to its spectrophotometric detection. The method consisted of the complexation of Co(II) with pyrocatechol violet (PV) followed by the preconcentration of the Co(II)-PV complex using VALS-DLLME and then an absorption measurement at 600 nm. The optimum conditions for complex formation were a 1 : 3 mole ratio of Co(II) and PV at pH 7.5, while the conditions for VALS-DLLME were 300 mL 1-dodecanol as extraction solvent, and 300 mL acetonitrile as dispersive solvent under a vortex for 20 s with the addition of cationic surfactant (0.02 mmol L À1 CTAB). Under the optimum conditions, good linearity was in the range of 0.1-10 mg L À1 , the enrichment factor (EF) was 13.5 and the low limit of detection (LOD) was 0.04 mg L À1 . The method was applied to the analysis of Co(II) in water, green leaf vegetable and vitamin B 12 samples. The proposed method provided good recoveries in the range of 86-104%, which were comparable to those obtained from flame atomic absorption spectrophotometry. Results and discussionOptimization for the formation of Co(II)-PV complex Absorption spectra. The Co(II)-PV complex has blue color with the maximum absorption wavelength at 590 nm, while PV is yellow color with the maximum absorption wavelength at 7244 | RSC Adv., 2018, 8, 7243-7251 This journal is Fig. 1 (a) Absorption spectra of Co(II)-PV complex at different concentrations of Co(II) obtained from direct analysis (left) and with VALS-DLLME (right). Conditions of complexation: molar ratio (Co(II) : PV) of 1 : 3, phosphate buffer pH 7.5. Condition of VALS-DLLME: 300 mL 1-dodecanol, 0.02 mmol L À1 CTAB, 300 mL acetonitrile, 0.2 g Na 2 SO 4 , vortex at 3200 rpm for 40 s. (b) Effect of the PV concentration. Conditions: 1.00 mg L À1 Co(II) and phosphate buffer pH 7.5. (c) Effect of pH. Conditions: 1.00 mg L À1 Co(II) and 0.06 mmol L À1 PV in phosphate buffer.This journal is

A Vortex-Assisted Dispersive Liquid-Liquid Microextraction Followed by UPLC-MS/MS for Simultaneous Determination of Pesticides and Aflatoxins in Herbal Tea

“…The role of the dispersive solvent converts the extraction solvent into droplets in an aqueous sample to help the analytes transfer into the organic phase. The dispersive solvents not only has a good solubility with the extraction solvent but also is miscible with water [42,43]. In the DLLME method, acetonitrile, acetone and methanol are usually chosen as the dispersive solvents.…”

Optimization of Effervescent Tablet-Assisted Dispersive Liquid-Liquid Microextraction with Central Composite Design for Preconcentration of Stimulant Drug

“…The results illustrated in Figure 4 shows that by increasing the volume of 1-dodecanol, the peak height response increased, and optimized when it reached volume 468 µL. The 1-dodecanol (log k ow 5.13) will become a good extractant as the solvent fulfilled several requirements, such as hydrophobic solvent (solubility 0.004 g L -1 ), low volatility, low density (0.830 mg L -1 ), and low melting point of below room temperature (22-24 °C) (Chaiyamate et al 2018;Jing et al 2018;Przyjazny 2019). Hydrophobic end and hydrogen bond donors played a significant role in extracting the targeted analyte (Hu et al 2017;Zheng et al 2017).…”

Surface-Active Ionic Liquid-Assisted Cloud Point Extraction for Pre-Concentration and Determination of Cobalt Ions in Pharmaceutical Preparations

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