汞的毒性

汞对人体的毒性 ,在很大程度上决定于它的存在形式。汞和甘汞 (氯化亚汞 )等难溶于水 ,不容易被胃肠吸收 ,因此毒性小。但是 ,经呼吸道吸入则易使机体中毒 ,因为肺泡的吸收率比肠粘膜高得多 ,无机汞在肠道的吸收率小于 5% ,肺泡的吸收率却高达 80 %。同时 ,由于汞可以流动 ,又易挥发 (甘汞也易挥发 ) ,很容易扩散到脑和血液中 ,从而造成汞中毒。能溶于水的无机汞化合物 ,容易被肠道吸收 ,如升汞 (二氯化汞 )则毒性很强 ,内服 0 2～ 0 4克便可致死。有机汞化合物 ,如甲基汞、乙基汞、二甲基汞等 ,其毒性极强。由于它们能溶解在脂肪中 ,很容…     

汞代N-乙烯基咔唑-丙烯酸共聚物的合成与研究

制备线型和网状N-乙烯基咔唑-丙烯酸甲酯共聚物后,用三氟乙酸汞分别在四氢呋喃(THF)和二氯甲烷中进行汞化反应,得到相应的线型和网状汞代咔唑共聚物。这些共聚物经THF溶解或溶胀后,用氢氧化钠水溶液水解,得到相应的水溶性线型高分子和吸水性网状高分子,憎水性汞代咔唑共聚物在THF中由I₂取代汞;亲水性汞代咔唑共聚物在水溶液中由KI₃取代汞。汞代咔唑高分子链在不同溶剂中可以产生不同的形态变化。     

汞代N—乙烯基咔唑—丙烯酸共聚物的合成与研究

制备线型和网状Ｎ－乙烯基咔唑－丙烯酸甲酯共聚物后，用三氟乙酸汞分别在四氢呋喃和二氯甲烷中进行汞化反应，得到相应的线型和网状汞代咔唑共聚物。这些共聚物经ＴＨＦ溶解或溶胀后，用氢氧化钠水溶液水解，得到相应的水溶性线型高分子和吸水性网状高分子，憎水性汞汞代咔唑共聚物在ＴＨＦ中由Ｉ２抽代汞；亲水性汞代咔唑共聚物在水溶液中由ＫＩ３取代汞、汞代咔唑高分子链在不同溶剂中可以产生不同的形态变化。     

冷原子吸收光谱法直接测定尿汞

汞属于剧毒物质,进人人体的无机汞可转变为毒性更大的有机汞,引起全身中毒作用.目前测定尿汞的方法主要有冷原子吸收光谱法、冷原子荧光法.尿样的前处理多采用常压湿法消解,存在试剂消耗量大,处理时间长,回收率低等缺点.本工作采用不进行消化处理直接取样,采用冷原子吸收光谱法测定职业人群的尿汞,此法快速、简单、试剂用量少,回收率高.     

冷原子吸收光谱法测定鱼体内不同组织中的汞含量

汞在水生生物体中有很强的富集效应,并可通过食物链富集进入人体,具有生物致畸、免疫毒性,神经毒性效应。1956年日本的水俣病就是典型的汞中毒事件,其中多人因误食含汞的鱼肉而死亡。鱼是人们主要的肉类食物之一,对鱼体汞含量的监     

以聚苯乙烯树脂为载体的缩硫醛大环螯合树脂的合成和性能研究

以大孔聚苯乙烯树脂为载体,合成了具缩硫醛大环的螯合树脂。它对Hg~(2+)的络合容量可达30—60mgHg~(2+)/g树脂,比对Ca~(2+)、Zn~(2+)、Cd~(2+)、Pb~(2+)等金属离子的络合容量高数百倍.它能够使因汞中毒而失活的脲酶恢复活力的能力优于巯基树脂及通用阴离子交换树脂。有可能作为口服的高分子解汞毒药物。     

刺梨利康饮对汞中毒大鼠汞铜锌含量的影响

用高汞水喂养大鼠8周,复制出慢性汞中毒模型,再分别自由饮用利康饮饮料和腹腔注射二巯基丙磺酸钠3周,探讨刺梨利康饮和二巯基丙磺酸钠对慢性汞中毒大鼠体内汞、铜、锌含量的影响.结果显示:慢性汞中毒引起血清、肝、脑和肾中汞含量升高的同时,引起血清、脑和肾中铜、锌含量及肝中锌含量降低;利康饮可降低血清和肾中汞含量,并可提高血清、脑和肾中铜、锌含量及肝中锌含量;二巯基丙磺酸钠虽可降低血清、肝和肾中汞含量,升高血清和肾中铜含量,但引起血清和肝中锌含量更加降低.结果表明:利康饮可降低慢性汞中毒大鼠体内汞的负荷量,并具有补充铜、锌微量元素的作用.     

剌梨利康饮对汞中毒大鼠汞铜锌含量的影响

用高汞水喂养大鼠８周,复制出慢性汞中毒模型,再分别自由饮用利康饮饮料和腹腔注射二巯基丙磺酸钠３周,探讨剌梨利康饮和二巯基丙磺酸钠对慢性汞中毒大鼠体内汞、铜、锌含量的影响。结果显示：慢性汞中毒引起血清、肝、脑和肾中汞含量升高的同时,引起血清、脑和肾中铜、锌含量及肝中锌含量降低;利康饮可降低血清和肾中汞含量,并可提高血清、脑和肾中铜、锌含量及肝含量;二巯基丙磺酸钠虽可降低血清、肝和肾中汞含量,升高血清     

hgcA/B基因介导的汞甲基化分子机制及其应用

作为一种强神经毒性物质,环境中的甲基汞(MeHg)主要由产甲烷菌、硫酸盐还原菌、铁还原菌等厌氧微生物产生,可通过水生食物链积累并作用于人体。汞甲基化基因hgcA/B明确以后,不仅扩大了可探知的汞甲基化微生物范围,也为汞甲基化生物分子机制的探索提供了新的方向。本文1)概述了hgcA/B及其表达产物HgcA、HgcB的预测结构和生物体内的汞甲基化分子机制,2)讨论了基于hgcA/B的环境汞甲基化研究进展,3)总结了现有hgcA/B研究存在的不足,4)对汞甲基化基因领域的研究方向进行了展望。     

DMA-80 型直接测汞仪测定食品中汞

汞可引起人类急、慢性中毒,自工业革命以来,汞在全球大气、水和土壤中的含量已增加了3倍左右.在工业区附近汞的含量更高,汞污染的不断加剧对人类健康和环境造成了极大危害.     

Plasticized open-cell polyurethane foam as a universal matrix for organic reagents in trace element preconcentration : Part II. Collection of mercury traces on dithizone and diethyldithiocarbamate foams

The analytical suitability of zinc dithizonate foam for the collection and preconcentration of traces of mercury(II) has been examined. The effect of pH, plasticizer and chelating agent concentration on the collection rate of mercury has been critically investigated. The capacity for mercury(II) of a TBP-plasticized zinc dithizonate foam at pH 6 is 23.4 μeq g^?1. The effect of plasticizer on the rate of recovery of mercury with sodium thiosulphate solution is also discussed. The preparation of zinc diethyldithiocarbonate foam is described. Traces of mercury(II) can also be collected rapidly and quantitavely by this foam.     

Synthesis of chitosan-based resins modified with tris(2-aminoethyl)amine moiety and its application to collection/concentration and determination of trace mercury by inductively coupled plasma atomic emission spectrometry

A novel chitosan-based chelating resin modified with tris(2-aminoethyl)amine moiety (CCTS-TAA) was synthesized, and its characteristics in the collection/concentration of mercury was examined. The synthesized resin showed good adsorption toward mercury in a wide pH range, and the adsorbed mercury can be easily eluted by using 2M HNO(3) without any addition of complexing agent. The resin was then packed in a mini-column and the mini-column was installed on a computer-controlled automated-pretreatment (Auto-Pret) system coupled with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for on-line mercury collection and determination at trace level.     

Luminescent bacteria-based sensing method for methylmercury specific determination

A bacterial biosensor method for the selective determination of a bioavailable organomercurial compound, methylmercury, is presented. A recombinant luminescent whole-cell bacterial strain responding to total mercury content in samples was used. The bacterial cells were freeze-dried and used as robust, reagent-like compounds, without batch-to-batch variations. In this bacteria-based sensing method, luciferase is used as a reporter, which requires no substrate additions, therefore allowing homogenous, real-time monitoring of the reporter gene expression. A noninducible, constitutively light-producing control bacterial strain was included in parallel for determining the overall cytotoxicity of the samples. The specificity of the total mercury sensor Escherichia coli MC1061 (pmerRBlux) bacterial resistance system toward methylmercury is due to a coexpressed specific enzyme, organomercurial lyase. This enzyme mediates the cleavage of the carbon–mercury bond of methylmercury to yield mercury ions, which induce the reporter genes and produce a self-luminescent cell. The selective analysis of methylmercury with the total mercury strain is achieved by specifically chelating the inorganic mercury species from the sample using an optimized concentration of EDTA as a chelating agent. After the treatment with the chelating agent, a cross-reactivity of 0.2% with ionic mercury was observed at nonphysiological ionic mercury concentrations (100 nM). The assay was optimized to be performed in 3 h but results can already be read after 1 h incubation. Total mercury strain E. coli MC1061 (pmerRBlux) has been shown to be highly sensitive and capable of determining methylmercury at a subnanomolar level in optimized assay conditions with a very high dynamic range of two decades. The limit of detection of 75 ng/l (300 pM) allows measurement of methylmercury even from natural samples.     

Determination of total and methyl mercury in human permanent healthy teeth by electrothermal atomic absorption spectrometry after extraction in organic phase

A simple and sensitive method has been developed for determination of inorganic and methyl mercury in biological samples by ETAAS. For determination of methyl mercury; it was transferred to toluene phase by acid leaching extraction method. For total mercury after digestion of samples; it was extracted to toluene phase by means of the chelating agent diethyldithiocarbamate. Formation of complex between MeHg and diethyldithiocarbamate enhance the MeHg signal and increases the reproducibility. Furthermore, Pd-DDC was used as modifier for both mercury and methyl mercury determinations. The optimization performance was independently carried out by modifying the parameters such as temperature of mineralization, atomization and gas flow rate for methylmercury and inorganic mercury in ETAAS. The limits of detection were 0.15 and 0.12 μg g⁻¹ for methyl mercury and total mercury, respectively. The repeatability of the measurements of whole procedure were 15.8% for methyl mercury and 16.9% for total mercury determination. The accuracy of the method has been investigated by means of spiking different amounts of methylmercury and inorganic mercury to the samples. The recoveries were found within the range of 88-95% for methyl mercury and 85-92% for total mercury. For determination of total mercury, the method was validated by CVAAS. The obtained results by the present procedure were in good agreement with those of the CVAAS. The proposed method was applied for 30 human permanent healthy teeth (without filling) which significant positive correlations were found among number of amalgam filling and total mercury and MeHg.     

Supercritical fluid extraction of organic and inorganic mercury from solid materials

Mercuric ions (Hg(2+)) can be extracted from solid samples (cellulose matrix) using methanol modified supercritical CO(2) containing the fluorinated chelating agent lithium bis(trifluoroethyl)dithiocarbamate (LiFDDC). Methylmercuric chloride (CH(3)HgCl) and dimethylmercury [(CH(3))(2)Hg] can be extracted by supercritical CO(2) without chelating agent and modifier. The solubility of Hg(FDDC)(2) in supercritical CO(2) has been determined to be 5 x 10(-3)M at 5O degrees C and 150 atm, which is about 3 orders of magnitude greater than that of the non-fluorinated analogue Hg(DDC)(2). Use of methanol (5%)-modified CO(2) further enhances the solubility of Hg(FDDC)(2) by a factor of 2.4. A small amount of water added to the sample matrix tends to facilitate the extraction of Hg(FDDC)(2) and CH(3)HgCl. Potential applications of this in situ chelation-supercritical fluid extraction method for the preconcentration of mercury species and treatment of mercury contaminated wastes are discussed.     

Effect of model organic compounds on square-wave voltammetric stripping analysis at the Nafion/chelating agent mercury film electrodes

The effect of various organic compounds on the Nafion/chelating agent mercury film electrodes (NCAMFEs) in square-wave anodic-stripping voltammetry (SWASV) is explored. Two chelating agents used to prepare the NCAMFEs are dimethylglyoxime and 2,2'-bipyridyl. Triton X-100, sodium dodecyl sulfate, albumin, gelatin, starch, camphor, and humic acid are used as model organic compounds, while cadmium, lead, and copper are used as test metal ions. The NCAMFEs are considerably more resistant to organic interferences than the Nafion-coated mercury film electrode. The implications of these interferences for the reliability and feasibility of stripping measurements using the NCAMFEs in real samples are discussed. Results presented for untreated urine and natural water samples demonstrate the analytical utility of the NCAMFEs in SWASV.     

微波辅助制备螯合纤维及其对汞的吸附性能

在微波辅助下,以聚丙烯腈纤维(PANF)为基体材料,二乙烯三胺(DETA)和硫化钠为改性试剂,通过两步接枝反应快速制备了含有大量硫原子的螯合纤维吸附剂。利用傅里叶变换红外光谱仪(FT-IR)和热重分析仪(TGA)对改性前后的纤维进行表征,同时考察了pH值、初始浓度、吸附时间和温度对螯合纤维吸附汞离子的影响。结果表明,微波辅助是一种高效、节能、经济和绿色的改性方法,改性过程在无毒的水环境中进行,试剂用量少,且改性时间大大缩短。改性纤维对汞离子的吸附是一个准二级动力学过程,较好的符合Langmuir吸附模型。在pH=7的条件下,螯合纤维对汞离子的最大吸附容量达到333.1mg/g,是一种有效的去除水中汞污染的吸附材料。     

Effects of several dithiocarbamates on tissue distribution and excretion of inorganic mercury in rats

The effects of various chelating agents, sodium N-benzyl-D-glucamine dithiocarbamate (BGD), sodium N-p-methylbenzyl-D-glucamine dithiocarbamate (MBGD), sodium N-p-hydroxymethylbenzyl-D-glucamine dithiocarbamate (HBGD), and N-p-carboxybenzyl-D-glucamine dithiocarbamate (CBGD), which were newly synthesized, and sodium N-methyl-D-glucamine dithiocarbamate (MGD), on the distribution and excretion of inorganic mercury were compared in rats exposed to HgCl2. Rats were injected i.p. with 203HgCl2 (300 micrograms of Hg and 74 kBq of 203Hg/kg) and 30 min or 24 h later, they were injected with a dithiocarbamate (1200 mumol/kg). At 30 min after mercury administration, BGD and MBGD significantly enhanced the biliary excretion of mercury, while CBGD, MGD, and HBGD enhanced the urinary excretion of mercury to a small extent. At 24 h after mercury injection, BGD was the most effective on the biliary excretion of the metal, while MGD and HBGD significantly enhanced the urinary excretion of the metal. All of these dithiocarbamates were effective in mobilizing mercury from the kidney at 30 min after mercury treatment. At 24 h after mercury treatment, HBGD and BGD effectively depressed mercury content in the kidney. These results show that the injection of BGD and HBGD at both 30 min and 24 h after mercury treatment can much more effectively mobilize mercury from the kidney without redistribution of mercury to other tissues, such as brain, heart, and lung, when compared with injection of other chelating agents. The pattern of mobilization and excretion of mercury following treatment with each chelating agent was related to the organic/aqueous partition coefficient of each dithiocarbamate-mercury complex.     

Amperometric complex-formation titrations of traces of copper

Copper has been determined in the submicrogram range by means of a eomplexometric titration with triethylenetetramine (TRIEN), the end-point being detected by following the anodic wave of the chelating agent at a rotating mercury electrode. The influence of the presence of other metals has been investigated both from the theoretical and the experimental point of view. Because of its higher selectivity TRIEN is preferred to other reagents of the EDTA group. The results show that copper can be determined in the presence of large amounts of most other metals.     

Glassy carbon electrode modified with organic�Cinorganic pillared montmorillonites for voltammetric detection of mercury

A glassy carbon electrode modified with organic?Cinorganic pillared montmorillonite was used for voltammetric detection of mercury(II) in water. High sensitivity is obtained due to the use of the montmorillonites which displays outstanding capability in terms of adsorbing mercury ion due to its high specific surface and the presence of multiple binding sites. The experimental parameters and the effect of a chelating agent were optimized to further enhance sensitivity and selectivity. Linear calibration curves were obtained over the Hg(II) concentration range from 10 to 800???g?L^?1 for 5?min accumulation, with a detection limit of 1???g?L^?1. Simultaneous determination of Hg(II) and Cu(II) was also studied, and no interference was observed.