Yangjuan Wang,Kejing Du,Yifu Chen,Yijun Li,Xiwen He
Green octahedral crystals of MIL-101(Cr) were synthesized and used for the determination of Pb2+ at the trace level by differential pulse anodic stripping voltammetry (DPASV) because of their good adsorption capability for Pb2+. The synthesized MIL-101(Cr) was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Parameters affecting the electrochemical process, such as the pH of the electrolyte solution, the volume of the MIL-101(Cr) suspension, the potential and the time for accumulation, were investigated in detail. Under optimal conditions, the electrochemical sensor had a linear response over the concentration range of 1.0 × 10−9 to 1.0 × 10−6 mol L−1 (R2 = 0.999) with a detection limit of 5.0 × 10−10 mol L−1 (S/N = 3). The method was successfully applied to the determination in real samples and good recoveries are obtained from different spiked samples.
A novel method for the determination of ultratrace Pb in seawater by solution-cathode glow discharge atomic emission spectrometry (SCGD-AES) coupled with hydride generation (HG) has been developed. In the SCGD process, the hollow Ti tube, which can introduce gas instead of a solid tungsten rod is used as a discharge anode and combined with hydride generator. HG technology can not only separate Pb from a seawater matrix and reduce the matrix interference on detection, but can also significantly improve the transfer and atomization efficiencies for SCGD-AES. The optimum working conditions for HG and SCGD-AES for quantitative analysis of Pb were determined as 1% H 2 C 2 O 4 as the masking agent and addition of 3% formic acid to increase Pb volatilization . The limit of detection (LOD) for Pb was decreased by two orders of magnitude in comparison to the SCGD-AES process alone. Under optimal conditions, the LOD for Pb was 0.17 μg L −1 , and the relative standard deviation was 2.1% ( n = 11) for 100 μg L −1 Pb in artificial seawater. The proposed quantification method was verified using a seawater reference material (BWQ7001-2016), and the obtained results agreed well with certified values. Finally, the approach was used to quantitatively analyse Pb in seawater, and the results agreed well with those obtained by inductively coupled plasma mass spectrometry . The recoveries of standard addition were between 96.0% and 103.0%.
Yan Zhou,Xiaofang Yang,Leshou Zhang,Shaodui Ye,Ya Liu,Ning Lu,Yong Liu,Xiaodong Wen
Developing a fast, simple, and efficient sample pretreatment method is of great practical significance for the analysis of complex matrix samples. In this study, a novel multifunctional “four-in-one” effervescent tablet based on switchable hydrophobic deep eutectic solvent (SHDES) was prepared, which can simultaneously facilitate the in situ synthesis of SHDES and CO 2 generation, phase transition, and phase separation. The effervescent tablet based on the SHDES-assisted microextraction (ETA-SHDES-ME) technique was combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for the determination of Pb 2+ in Pinellia ternata (Thunb.) Breit. The important parameters affecting the extraction efficiency of Pb 2+ were optimized using the Box-Behnken design (BBD). The enrichment factor (EF) and limit of detection (LOD) of the established method for Pb 2+ are 31 and 0.2 μg/L, respectively, offering a fast, simple, and eco-friendly approach, and has the application potential of field analysis.
危险品化学品经营许可证（带存储）