Four complexes, [Cu4L2(OCH3)2(CH3OH)2]·2H2O (1), [Zn2L2Cl4]·2H2O·2CH3OH (2), [Hg2L2Br4]·4CH3OH (3), and {[CdL2Cl2]·4H2O·4CH3OH}n(4), have been synthesized and characterized from a bis(pyridylhydrazone) ligand (L) with copper(II), zinc(II), mercury(II) or cadmium(II), respectively. Complex1exists as a centrosymmetric tetranuclear dimer withLas deprotonated tridentate ligand. Complexes2and3exist as centrosymmetric metallamacrocycles withLas bidentate ligand. Complex4exists as a 1D looped-chain coordination polymer. The thermal stabilities and vapor adsorption properties of the four complexes were investigated as well.Keywords:pyridylhydrazone;complex;crystal structure;vapor adsorption
Cadmium, tin, mercury, and lead are four widespread metals in our environment from natural sources and human activities, and their toxic, metabolic, and bioavailable properties are chemical form-dependent. Considering large sample capacity in food, environmental and related fields, efficient, sensitive, inexpensive, and green methodologies are preferred for quantifying cadmium, tin, mercury, and lead compounds in an analytical trial. Herein we proposed a tetra-elemental method for simultaneous measurement of Cd, Sn, Hg, and Pb compounds by interfacing high-performance liquid chromatography with inductively coupled plasma mass spectrometry. The tetra-elemental method measured 12 metal compounds within 24 min in satisfactory precisions (<4.3 %) and low detection limits (0.022, 0.011–0.15, 0.016–0.028, and 0.013–0.021 μg L −1 for Cd(II), five tin compounds, three mercury compounds, and three lead compounds, respectively). By applying the proposed tetra-elemental speciation method to shrimp and fish, we found Cd(II) (0.043 mg kg −1 ) presented only in shrimp and methylmercury (0.8–4.6 μg kg −1 ) in both shrimp and fish with the absence of all targeted Sn and Pb compounds, which were far below the maximum limits by China GB 2762-2022. Overall, the proposed method offered significant advantages in analytical, economic and environmental aspects with good applicability to a wide range of food, environmental, and biological samples.
A simple and miniature analytical system was developed to determine Hg and Cd in small amounts of samples by integrating flow injection capillary liquid electrode discharge (CLED) optical emission spectrometry (OES) and microplasma-induced vapor generation (PIVG) atomic fluorescence spectrometry (AFS). With the assistance of the inherent capillary driving force and the force arising from the solution vaporization in the microplasma, the sample solution was automatically transported into the discharge chamber wherein analytes were simultaneously excited to generate their atomic emission lines and converted to their volatile species. Subsequently, the volatile species were further swept into AFS for their further determination. Therefore, the same sample could be successively analyzed by OES and AFS. Owing to the unique independent linear-range and sensitivity of CLED-OES and PIVG-AFS, the developed system not only significantly extended its linear range to 6 orders of magnitude but also remarkably reduced the sample consumption to several microliters. Thus, wide linear-range and ultrasensitive determination of Hg and Cd in limited amounts of samples were accomplished simply by sharing one single capillary liquid electrode discharge source. Under the optimized conditions, limits of detection (LODs) of 10 μg L–1 were obtained for both Hg and Cd when CLED-OES was used as a detector, whereas the LODs for Hg and Cd were improved to 0.03 μg L–1 and 0.04 μg L–1 with AFS detector, respectively. In addition, the extremely wide linear-range of 0.001–100 mg L–1 and 0.001–40 mg L–1 were obtained for Hg and Cd, respectively. The potential application of this method was validated by successfully analyzing three Certified Reference Materials (ZK021-1, GBW(E)090033, and GBW(E)090034) and six human blood samples.
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