Solid-state Reactions of Mercury with Pure Noble Metals Part 2. Mercury–iridium system

Thermogravimetry, cyclic voltammetry and other analytical techniques were used to study the reactions of mercury with pure iridium. The results allowed to suggest when subjected to heat or anodic stripping voltammetry an electrodeposited mercury film reacts with Ir substrate and at least three mass loss steps and three peaks appear in the mercury desorption process. The first two were attributed to Hg(0)species removal like a mercury bulk and a mercury monolayer. The last can be ascribed to the mercury removal from a solid solution with iridium. This revised version was published online in July 2006 with corrections to the Cover Date.     

High Pressure Behavior of Mercury Cyanamide HgCN2

Using the diamond anvil cell technique, angle‐dispersive X‐ray diffraction and Raman spectroscopy were employed to study the high pressure behavior of mercury cyanamide. Its decomposition under pressure starts at 1.9 GPa and is not completed even up to 10 GPa. The decomposition product α‐Hg transforms to β‐Hg during 7–10 GPa, while the C/N residual is not detectable by X‐ray diffraction. The zero pressure bulk modulus of mercury cyanamide is estimated as 38.5 GPa.     

大气中二价汞(Hg2+)的测定

用ＫＣｌ涂层的扩散管（ＫＣｌｃｏａｔｄｅｎｕｄｅｒ）测定了大气中的二价汞（Ｈｇ２＋）。实验结果表明：扩散管对Ｈｇ２＋的吸附率＞９５％;对Ｈｇ０的吸附率＜５％,实验所用的扩散管对Ｈｇ２＋最大吸附量不超过３０ｎｇ,所吸附的Ｈｇ２＋可以用１ｍｏｌ·Ｌ－１ＨＣｌ定量解吸,冷原子荧光测定Ｈｇ,回收率＞９８％。选择贵州某汞矿区冶炼车间,测定的Ｈｇ２＋含量为５４～７３ｎｇ·ｍ－３,约占大气总汞浓度的１０％～１５％。     

Reduction of 2-Bromo-4, 4-dimethyl-2-cyclohexenone at Mercury. A study on inverted peaks in cyclic voltammetry

The parameters which influence the inverted wave appearing in the reverse (oxidation) sweep in the cyclic voltammogramme of the title compound 1 are discussed in detail. The inverted wave is due to the interaction of the reduction products of 1 with the electrode and the electrolyte (TBAFB). The key condition for the presence of the inverted peak is a slow scan rate on the reverse sweep, at least for the last 50 mV before the inversion of the current-potential curve.     

高效液相色谱-电感耦合等离子体质谱(ICP-MS)法测定中药材中无机汞、甲基汞、乙基汞

为准确测定中药材中不同形态的汞含量,通过选用人工胃液作为提取液,经水浴加热提取后,以甲醇-乙酸铵为流动相,采用C18反相色谱柱对样品溶液进行分离,最后经电感耦合等离子体质谱(ICP-MS)法测定3种汞形态化合物的含量。建立了中药材中无机汞、甲基汞、乙基汞的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)法的测定方法,结果表明,3种汞形态化合物在0.5～5 ng/mL范围内均获得良好的线性关系,相关系数均大于0.999。通过加标回收的方法进行准确性评价,加标回收率为75.5%～118%,相对标准偏差RSD为2.4%～9.7%。测定的106批次中药材中,均未检出甲基汞、乙基汞。无机汞检出率为88.7%,合格率为100%。方法能够准确、高效地测定中药材中3种汞形态化合物的含量。106批次中药材中的汞存在形态主要是以无机汞为主。考察的106批次根及根茎类中药材中3种汞形态化合物的含量,积累了基础数据,为中药饮片的质量安全性监管提供技术支撑。     

新试剂3,3'-二甲基联苯重氮氨基-4-苯基-2-噻唑分光光度法测定废水中微量汞

研究了新试剂 3,3′-二甲基联苯重氮氨基 - 4 -苯基 - 2 -噻唑( DMDPDAPT)在表面活性剂 N-氨代十六烷基吡啶 ( CPC)存在下 ,与汞 ( )显色反应的适宜条件。在 p H7.2～ 9.2范围内 ,汞 ( )与 DMDPDAPT形成2∶ 2紫红色配合物 ,其最大吸收波长为 56 0 nm,配合物的表观摩尔吸光系数ε=9.0 1× 1 0 4L· mol-1· cm-1。汞 ( )浓度在 0～ 1 2μg/2 5m L范围内符合比尔定律。此法已用于废水中微量汞 ( )的测定。     

Mercury in organic chemistry. 19. Rhodium promoted methylation of organomercurials

Alkenyl-, alkynyl- and arylmercurials are methylated in excellent yield upon treatment with stoichiometric amounts of CH₃RhI₂(PPh₃)₂ ($\text{1}$). Catalytic methylation of these organomercurials is possible using $\text{1}$ and methyl iodide, but side reactions interfere.     

A Critical Comparison of Hanging Mercury Drop Electrode and Long Lasting Sessile Drop Mercury Electrode in A.C. Anodic Stripping Voltammerty

Abstract

The hanging mercury drop electrode (HMDE) and the long lasting sessile drop mercury electrode (LLSDME) currently used in trace metal analysis are critically compared. Alternating current anodic stripping voltammetry (AC-ASV) and alternating current linear sweep voltammetry (AC-LSV) respectively are employed for the determination of Zn,Cd, Pb, Cu and Fe.

The influence of the electrolysis time, stirring rate, a.c. amplitude, frequency and scan rate on the peak current is evaluated.

Analytical measurements were carried out by the standard addition method, using 0.02 mol/l HClO₄ + 0.1 mol/l NaClO₄ (Zn, Cd, Pb, Cu) and 0.1 mol/l (COONa)₂, (Fe), respectively as supporting electrolytes.     

智能型测汞仪测定氟石粉中汞含量

近年来我国氟石粉的出口量不断增加,国外用户因生产工艺或环境保护等的要求,在国际贸易中对氟石粉又提出了更多更高的质量指标[1],合同规定的品质项目也不断增多,其中汞的含量要求<1μg·g-1,结合实际工作的需要,本法采用智能型测汞仪对其中的汞含量进行测定,其原理即汞原子对波长为253.7nm的共振谱线有强烈的吸收作用,吸收的大小与汞原子蒸汽浓度的关系符合比耳定律[2]。试样只需经硝酸[3]、重铬酸钾[4]处理后,即可用测汞仪于波长253.7nm处进行测定,测定范围为0.00001%～0.001%。方法操作简便、迅速,准确可靠,可操作性强。1　试验部分1…     

测汞仪直接测定食品中总汞

建立了食品中总汞快速准确的测定方法。使用测汞仪,采用样品直接进样法,对芹菜、大葱、鸡肉等10种标准物质中的汞含量进行了测定,结果表明,在0.2~100ng范围内线性良好,10种标准物质的检测结果均在标示值范围内。使用测汞仪直接测定食品中总汞含量,具有灵敏度高、快捷、不受前处理影响等优点,便于推广,适用于各类食品中总汞的快速测定。     

汞与社会

汞是室温下为液态的唯一金属,它有许多特殊性质(熔、沸点低,密度大,表面张力大,挥发性高,剧毒等),所以它与社会的关系与其他金属大不相同。在古代由丹砂到炼丹术,由水银到汞齐,应用技术的发展不仅推动物质文明进步,还牵动着社会贫富阶层利益之争。近代化学科学开拓了汞的应用领域(电化学,仪表、催化、农业、医药等)同时也扩大了汞的污染范围。利用汞的特性,防治汞的毒性,应是今后社会长期的努力方向。     

Mercury(II) 2-aminoethanethiolate clusters: intramolecular transformations and mechanisms

The combination of HgF2 and 2-aminoethanethiol (AET, with some AET.HCl present) yielded a cyclic tetranuclear thiolate, [Hg4Cl4(SCH2CH2NH2)4] (1), with alternating Hg and S atoms. The Cl from the reaction mixture led to the formation of Hg-Cl bonds with no Hg-F in the final product. In contrast, a similar reaction with HgBr2 yielded a nonanuclear cluster, [Hg9Br15(SCH2CH2NH3)15]3+ (2), and the disulfide salt {[HgBr4][(NH3CH2CH2S-)2]} (3). Despite similar reactions, the AET groups in 2 are protonated compared to the nonprotonated amine groups in 1, which allows the ligand to chelate the Hg atom in the latter compound. The reaction with HgI2 yielded a cyclic tetranuclear compound, [Hg4I6(SCH2CH2NH2)2(SCH2CH2NH3)2](H2O/EtOH) (4), containing protonated and nonprotonated AET groups. Compound 4 at room temperature irreversibly rearranges to [Hg4I4(SCH2CH2NH2)4] (5), which is isostructural to 1. A systematic pathway for the formation of 1 along with the intramolecular conversion of 4 to 5 is proposed. These compounds demonstrate that very diverse Hg-S compounds form under similar reaction conditions.