Spectrophotometric determination of trace amounts of Sb(III) and Sb(V) in water and biological samples by in-tube dispersive liquid–liquid microextraction and air-assisted liquid–liquid microextraction

Optimization of [P6,6,6,14+]3[GdCl63-] magnetic ionic liquid assisted dispersive liquid-liquid microextraction for selective and sensitive determination of cadmium in environmental water and food

A simple and green hydrophobic magnetic ionic-liquid assisted dispersive liquid-liquid microextraction (MIL-DLLME) was optimized for the determination of trace cadmium (Cd (II)) in environmental and food samples by flame atomic absorption spectrophotometer. To achieve selective and sensitive extraction of Cd (II), four MILs were prepared and tested. Extraction parameters of the MIL-DLLME including pH, type and volume of the MIL, type and volume of dispersive solvent, extraction cycle, ionic strength and sample volume were investigated in detail and optimized by Box-Behnken design. Under optimum conditions, matrix effect, recovery study, intra-day and inter-day precision were performed for the MIL-DLLM. The analytical characteristics such as limit of detection, limit of quantification and pre-concentration factor were 0.17, 0.56 and 125 ng mL-1, respectively. The validation of the MIL-DLLME was evaluated by analysis of reference materials. Moreover, the accuracy of the results in the analysis of real samples was evaluated by standard addition and quantitative recoveries (91 ± 5-101 ± 2%) were achieved. The results obtained in the analysis of both reference materials and real samples showed that the MIL-DLLME has a selective applicability for cadmium.

Speciation of trace amounts of Sb(III) and Sb(V) in environmental water using inductively coupled plasma mass spectrometry after magnetic solid-phase extraction with rGO/Fe3O4

We developed an approach of magnetic dispersive solid-phase extraction (MSPE) based on magnetic graphene nanocomposite rGO/Fe3O4 for the determination of trace Sb(III) and Sb(V) using inductively coupled plasma mass spectrometry (ICP-MS). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the sorbent. The adsorption behavior of Sb(III) and Sb(V) on rGO/Fe3O4 was investigated. The results showed that the adsorption capacity of Sb(V) was nearly zero at pH = 9, while Sb(III) could be well adsorbed on rGO/Fe3O4. The magnetic SPE parameters including pH, adsorbent dosage, eluent type, and volume were optimized. The detection limit of Sb(III) under ideal conditions was 6 ng L-1, and the relative standard deviation was 7.6% (c = 1 g L-1, n = 7). The technique was used to identify Sb(III) at trace levels in environmental water samples, and its validity was examined by recovery experiments and the examination of an approved reference material.

Ultrasound assisted dispersive solid phase microextraction using polystyrene-polyoleic acid graft copolymer for determination of Sb(III) in various bottled beverages by HGAAS

A new polyoleic acid-polystyrene (PoleS) block/graft copolymer was synthesized and applied as adsorbent for ultrasound assisted dispersive solid phase microextraction (UA-DSPME) of Sb(III) in different bottled beverages and analysis using hydride generation atomic absorption spectrometry (HGAAS). Adsorption capacity of the PoleS was 150 mg g^-1. Several sample preparation parameters such as sorbent amount, solvent type, pH, sample volume and shaking time were optimized (based on central composite design (CCD) approach) and evaluated in respect to the recovery of Sb(III). The method revealed a high tolerance limit of matrix ions presence. Under optimized conditions, linearity range, the limit of detection, the limit of quantitation, extraction recovery, enhancement factor, preconcentration factor were 5-800 ng L^-1, 1.5 ng L^-1, 5.0 ng L^-1, 96%, 82, 90, respectively. Accuracy of the UA-DSPME method was confirmed based on different certified reference materials and standard addition method. Factorial design was utilized to estimate the influences of variables of recovery of Sb(III).

Supramolecular solvent-based liquid phase extraction of antimony prior to spectrophotometric quantification

Antimony (Sb) is highly hazardous to human health even in minute concentration. Therefore, its accurate and precise determination in the real environmental samples is of immense importance. In this work for the first time, UV-Vis spectrophotometric method was developed for the quantification of Sb(III) from water samples using supramolecular solvent (undecanol-tetrahydrofuran)-based extraction. The maximum absorption wavelength for antomony-diathizone complex was found to be 590 nm having molar absorptivity of 3.1 × 10⁴ L.mol.cm^-1. Factors affecting extraction efficiency like solution sample volume, amount of chelating agent, pH, matrix effect, and type and volume of supramolecular solvent were determined and optimized. Analytical parameters like limit of detection (0.19 µg L^-1), limit of quantification (0.62 µg L^-1), pre-concentration factor (15), enhancement factor (15), and relative standard deviation for 8 successive analysis (0.8%) were calculated under optimized experimental conditions. The method was applied to real water samples like tap water of laboratory, waste water from Kohat hospitals, and dam water (Tanda dam Kohat) with quantitative addition recovery (94-100%).