Electroanalytical Study of the Composition of the Raw Pigment Mixtures that Yield the Metallic Lustre on Ceramics. A Link Between Composition and Final Result

Voltammetry of immobilized microparticles was used to study the electrochemistry of the raw pigments that produce the metallic lustre on ceramics after a successful firing. To study this influence of the mixture components on the reduction properties to achieve the metallic lustre, 14 mixtures of illitic clay, Fe₂O₃, HgS, CuO and AgNO₃ were prepared and studied in different media. Iron oxide improves the yield of the reduction of the metals and cinnabar helps a closer reduction of silver to copper reduction and prevents the Ag? Cu alloying because of the formation of silver–mercury adducts. The presence of one of the metals influences the peak position of the other metal. The use of vinegar as diluting agent is not casual, because in this media the reduction of silver takes place at a potential closer to the copper. This electroanalytical technique allowed to distinguish between powders of different composition and offered some information about the role of the components in the reduction of copper and silver and the selection of vinegar to prepare the raw pigment suspensions.     

Observation of the Cinnabar Phase in ZnSe at High Pressure

In this paper we describe the results of an energy dispersive X-ray diffraction experiment carried out in the ZnSe 1 m x Te x alloy and pure ZnSe under high pressure. In the downstroke the cinnabar phase is observed between the rocksalt and the zincblende phases. The analysis of the whole series of compositions ( x =0, 0.05, 0.1 and 0.2) enables us to establish its lattice parameters in ZnSe ( a =3.785 + and c =8.844 + at 10.5 GPa). The X-ray diffraction pattern simulation suggests that the internal parameters u and v are close to 0.5, indicating that the cinnabar phase in ZnSe is similar to that observed in GaAs and ZnTe. The cinnabar's stability range decreases as the Te content is reduced.     

X-ray Diffraction Study of Cd 0.8 Zn 0.2 Te Under High Pressure and Temperature

Energy dispersive X-ray diffraction using synchrotron radiation has been used to study phase transformations of Cd 0.8 Zn 0.2 Te under high pressure and temperature. We confirm the presence of a cinnabar phase between the zinc-blende and rock-salt phases. But contrary to the results in CdTe, this intermediate phase is found to be stable only on pressure decrease and in a narrower pressure and temperature range. Single-phase cinnabar patterns are obtained only at 300 and 373 K. At 673 K and above, even on pressure decrease, no evidence of the cinnabar phase is found. In this temperature range, a phase segregation phenomenon is observed in the zinc-blende phase during the zinc-blende transition in both upstroke and downstroke, and the retrieved sample at ambient conditions presents a double pattern corresponding to two different Zn contents.     

Direct analysis of mercury in Traditional Chinese Medicines using thermolysis coupled with on-line atomic absorption spectrometry

The purpose of this study is to develop and apply a mercury analyzer system capable of quantitative analysis of mercury in Traditional Chinese Medicines (TCM) drugs in the concentrations range from ng g⁻¹ to mg g⁻¹. No sample pre-treatment was needed and this greatly simplifies the analytical procedure and minimizes potential sources of contamination. The precisions of analyzing solid mercury standard sample and real TCM materials were 2.1% and 2.5-8.2%, respectively; and the recovery based on the analysis of standard reference materials ranged from 95.2% to 105%. The performance of the method has been compared with inductively coupled plasma-mass spectrometry (ICP-MS) technique and excellent agreements were observed between the two methods. The method has been applied to the investigation of Hg content in several TCM drugs containing or not containing cinnabar. Mercury concentration in the same TCM products differs widely with different manufacturers, suggesting that external contamination and the Hg presence in raw herbal materials are the main sources of Hg. In addition, comparison of mercury thermal releasing profiles between TCM drug and cinnabar suggests that mercury conversion from cinnabar to biological matrices-bound Hg could occur because of the aid of other ingredients in the formulated drug.     

冰硼散中朱砂的含量测定

采用双硫腙比色法测定冰硼数中朱砂的含量．结果表明。该法分析结果准确可靠．RSD为1．17％，回收率102．7%．所需仪器普通。操作简单，快速。可供一般药厂生产中控制朱砂含量时参考．     

Investigation of metal-binding metallothioneins in the tissues of rats after oral intake of cinnabar

The multi-metal-binding MT fractions in rat tissues after oral intake of cinnabar were characterized by hyphenated size-exclusion chromatography (SEC) and inductively coupled plasma mass spectrometry (ICP–MS). With the increase of both the feeding time and dosage of cinnabar the amounts of Hg-binding MT fractions in rat kidney of groups fed cinnabar increased significantly compared with the control group. Meanwhile, more Cu-binding MT were synthesized in the rat kidney, which confirmed the manipulating effect of MT in the homeostasis of Cu for detoxification of nephritic mercury. Although the Hg-binding MT fractions in rat liver of all cinnabar groups were almost independent of cinnabar dosage (2.5–5.0 g kg^–1 bw) and feeding time (2–4 weeks), the amount was much higher than that of the control group. The amounts of Hg-MT in other rat tissues of the cinnabar groups and the control group were compared and their significance is discussed.     

Influence of chloride and sediment matrix on the extractability of HgS (cinnabar and metacinnabar) by nitric acid

The extractability of metacinnabar and cinnabar, alone or in the presence of some sediment components, with various concentrations of HNO₃ (1, 4, 6, and 14 M) was studied. Both forms of HgS (0.2–0.3 mg HgS in 10–20 mL of acid) were insoluble in all HNO₃ concentrations as pure compounds. The presence of FeCl₃ enhanced solubility of both cinnabar and metacinnabar, especially when concentrated HNO₃ was used for the extraction. As the same effect was not obtained in the presence of FeOOH, we concluded that chloride and not Fe³⁺ was responsible for HgS dissolution. In fact, addition of very low chloride concentration to concentrated HNO₃ provoked partial (Cl>10^–4 M) or even total dissolution (Cl>10^–2 M) of HgS. In dilute HNO₃ (4–6 M) cinnabar was much less affected by chloride addition than metacinnabar. Extraction of HgS by concentrated HNO₃ in the presence of sediment of various salinities demonstrated that the amount of dissolved HgS increased with the increase of the sediment salinity (from freshwater to estuarine and marine sediment), confirming that chloride enhances dissolution of HgS. Removal of chloride by washing the sediment with Milli-Q water significantly reduced dissolution of added HgS during extraction by concentrated HNO₃. These results demonstrate that conclusions based on the extraction schemes using concentrated HNO₃ as single extractant or as the first extractant in the sequential extraction procedures can be biased. A verification of artifactual oxidation of HgS, when using more concentrated HNO₃ as extractant, would help to verify reliability of the applied extraction procedure.     

固体热解塞曼原子吸收光谱法用于中药和生物样品中痕量汞的快速测定

建立了一种采用固体热解塞曼原子吸收光谱快速测定中药和生物样品中痕量汞的方法,样品不需要经过消解即可直接测定。考察了样品颗粒大小对分析结果的影响,在优化的实验条件下,方法的重现性为2.1％(峰面积)和9.1％(峰高),检出限为6.3 ng·g-1(3σ), 回收率为95%～105%。使用标准参考物质进行对照分析,通过与ICP-MS分析法的结果进行比较,结果令人满意。大鼠灌胃实验表明,长期灌胃较大剂量的朱砂对肾等组织有一定的毒害,而在部分传统中药中朱砂用量较高。文章对制定中药安全性标准具有参考意义。