The separation–preconcentration and determination of ultra-trace gold in water and solid samples by dispersive liquid–liquid microextraction using 4-ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) as chelating agent and flame atomic absorption spectrometry

A novel nanomotor (ZIF-L(Co)/WSe2 nanocomposite) for nanomotor motion-based dispersive micro-solid phase extraction (NM-d-μSPE) of gold and palladium

A novel method for the separation and enrichment of Au(III) and Pd(II) ions in mining stone and covering samples was developed, using ZIF-L(Co)/WSe2 as a nanomotor for nanomotor motion-based dispersive micro-solid phase extraction (NM-d-μSPE). The manufactured nanocomposite was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and electrochemical analyses. The motion dynamics of the nanomotor have been optimized by modifying the concentration of the fuel (H2O2) to achieve rapid and efficient movement, which enhanced adsorption performance. Important analytical parameters, such as pH, ligand and sorbent amounts, eluent type and volume, and the influence of matrix ions, were methodically studied. The method exhibited excellent sensitivity, with detection and quantification limits of 0.93 μg L-1 and 3.10 μg L-1 for Au(III) and 0.83 μg L-1 and 2.76 μg L-1 for Pd(II), respectively. The ZIF-L(Co)/WSe2 nanomotor showed exceptional adsorption efficiency for the simultaneous extraction of Au(III) and Pd(II) ions in the presence of H2O2 fuel. This method is reliable, fast, and simple, thus offering a useful method for the separation, enrichment, and quantification of Au(III) and Pd(II) in geological samples using flame atomic absorption spectroscopy (FAAS). Additionally, inductively coupled plasma-mass spectrometry (ICP-MS) was used to validate the NM-d-μSPE method.

Development of a dispersive liquid-liquid microextraction technique for ultra-sensitive detection of gold in environmental samples using atomic absorption spectrometry

The work examines the determination of gold from environmental samples by dispersive liquid-liquid microextraction (DLLME) method. The method was developed for the separation and determination of Au (III) ions after chelating with bis (salicylaldehyde) ethylenediimine (H2SA2en) Schiff-base as derivatizing reagent. Flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) techniques were used for quantitation of Au (III). These techniques are sensitive and rapid for the determination of gold concentrations in ore, water and sediment samples. The influence of factors such as pH, reagent concentration, solvents (extracting) (disperser) and solvent volumes on extraction efficiency of Au (III) ions were studied and optimized by univariate and multivariate techniques. The linearity of the method was in the range of 2 to 12 µg/L with R2 = 0.997. The limit of detection was 1 µg/L, and the limit of quantification was 3 µg/L. The preconcentration factor and enrichment factor values were 44 and 47. The repeatability (the intra-day) and reproducibility (the inter-day) precisions (n = 3) were found to be 0.417-3.56%. The proposed method was successfully applied for the determination of gold in sediment samples of the Indus River, Kori Barrage, goldsmith water, acidic solution of goldsmith and ornament samples collected from Goldsmith Labs and shops. The results found from FAAS were compared with those obtained from ICP-OES technique, and a good correlation with comparable selectivity and sensitivity was specified.