气相色谱法测定废水中的烷基汞

以巯基棉（ＳＣＦ）为吸附剂，用柱上富集技术，浓缩富集水中的烷基汞（氯代甲基汞，氯代乙基汞）。用少量的２ｍｏｌ／ＬＨＣｌ洗脱，用甲苯作萃取剂从洗脱液中萃取烷基汞。对于简单水体，该有机相可直接用于气相色谱测定；对于复杂水体，采用反萃取的方法测定，即可进一步浓缩，又可减少背景峰。用玻璃填充柱－电子捕获检测器响应的气相色谱法测定，最低检测限为８．６×１０￣（－１２）ｇ，可检测到废水中０．３４ｎｇ／Ｌ的单一烷基汞（２．５Ｌ水样）。对样品的保存条件也作了探索。     

毛细管气相色谱与原子吸收联用测定水貂皮及其毛发中的有机汞

用毛细管气相色谱与原子吸收联用对水貂皮及其毛发中的有机汞进行了分离测定，使用ＨＰ－１石英毛细管柱，在４．５ｍｉｎ内可以基线分离氯化甲化基汞（ＭＭＣ），氯化了基汞（ＥＭＣ）和氯化苯基汞（ＰＭＣ），分离后的组分在７００℃处原子后进行原子吸收测定，检测限分别为：ＭＭＣ０．１ｎｇ；ＥＭＣ０．０９ｎｇ；ＰＭＣ０．１ｎｇ。方法简便，快速，准确，可以有效地用于环境和生物样品中有机汞的分离测定。     

化学衍生—高效液相色谱法同时测定铅（Ⅱ）和汞（Ⅱ）

从吡啶－２－乙醛苯甲酰腙作柱前衍生试剂，在优化了衍生和色谱条件下实现了用高效液相以谱法同时测定铅和汞离子，在ｐｈｅｎｏｍｅｎｅｘｓｐｈｅｒｅｘＣ１８色谱柱上，用甲醇－水（６５：３５，Ｖ／Ｖ），作流动相，于２４８ｎｍ处检测，得到线性良好的工作曲线，铅和汞的最低检测限分别为２．５５μｇ／Ｌ和７．２９μｇ／Ｌ。分析了环境水样品和合成水样，铅和汞的标准加入回收率分别为９８．３％～１０１．７％和９８．０～１     

氯氮平的吸附伏安行为

在０．１ｍｏｌ／ＬＮＨ４Ａｃ（ｐＨ７．８）底液中，氯氮平（ＣＬＰ）在汞电极上有一线性扫描还原峰，Ｅｐｃ＝－１．３４Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）．该峰具有明显的吸附性，吸附粒子为ＣＬＰ中性分子．测得ＣＬＰ在汞电极上的饱和吸附量为２．７×１０－１０ｍｏｌ／ｃｍ２，每个ＣＬＰ分子所占电极面积为０．６２ｎｍ２，ＣＬＰ在悬汞电极上的吸附符合Ｆｒｕｍｋｉｎ等温式．测得吸附系数β＝６．２８×１０５，吸引因素γ＝０．７５，电子转移数ｎ为２，不可逆吸附的转移系数α为０．５３．探讨了ＣＬＰ在汞电极上的还原机理，并建立了吸附溶出伏安法测定ＣＬＰ的最佳条件，检测限为８．０×１０－９ｍｏｌ／Ｌ．     

奎宁负载树脂分离氢化物发生ICP—AES测定汞的研究

以奎宁为衍生试剂，将其负载在阳离子交换树脂上制成奎宁负载树脂。详细研究了Ｑ２ＣＲ对汞络阴离子的吸附行为。实验结果表明，在很宽的ＨＣｌ介质（从ｐＨ６至３ｍｏｌ／Ｌ）中，ＱＣＲ可定量吸附待测物汞，硫脲为定量解脱汞的理想试剂。在最佳实验条件下，ＱＣＲ对汞的吸附容量为１９．７ｍｇ／ｇ，当富集倍数为２０时，方法的检出限为１．４ｎｇ／ｍＬ，本法已应用于湖水人发中痕量汞的测定，分析结果满意。     

环境和生物样品中多来宝残留量的气相色谱分析方法研究

 湿性样品中的多来宝残留物用丙酮（水样和干样用石油醚）提取，提取液经石油醚再萃取、浓缩后，用被石油醚饱和的乙腈分配，过硅胶氧化铝混合柱净化，室温下与（ＣＨ３）３ＳｉＩ衍生化反应，生成３－苯氧基苄基碘，用ＧＣ检测。当添加浓度为０．０５，０．１０，１．００μｇ／ｇ时，样品的平均回收率为８０．７％～１１０．０％，方法最小检出量为０．０１ｎｇ，样品最小检出浓度是：水０．００１ｍｇ／Ｌ，稻米和土壤０．０１μｇ／ｇ，稻草、谷壳、水浮莲和罗非鱼为０．００８μｇ／ｇ。     

环境和生物样品中多来宝残留量的气相色谱分析方法研究

湿性样品中的多来宝残留物用丙酮（水样和干样用石油醚）提取，提取液经石油醚再萃取、浓缩后，用被石油醚饱和的乙腈分配，过硅胶氧化铝混合柱净化，室温下与（ＣＨ３）３ＳｉＩ衍生化反应，生成３－苯氧基苄基碘，用ＧＣ检测。当添加浓度为０．０５，０．１０，１．００μｇ／ｇ时，样品的平均回收率为８０．７％～１１０．０％，方法最小检出量为０．０１ｎｇ，样品最小检出浓度是：水０．００１ｍｇ／Ｌ，稻米和土壤０．０１μｇ／ｇ，稻草、谷壳、水浮莲和罗非鱼为０．００８μｇ／ｇ。     

冷原子—无色散原子荧光光谱法测定奶粉中汞的有关问题的探讨

本文第一次提出汞样品经硝酸消化后，汞（Ｈｇ）与氮氧化物（ＮｘＯｒ）形成络合物，在经典的加氯化亚锡（ＳｎＣｌ２）还原时，生成Ｈｇ与ＮＯ并能同时逸出，确定了Ｈｇ与ＮｘＯｒ存在配位关系，对汞的测定在数学计量上增加到１．５倍，结果表明，应用五氧化二矾消化奶样品能如实反映这一关系，并精确地得出其汞含量，在联合国环境规划署和粮食农业及世界卫生组织食品污染联合监测计划的第八届铅，镉，汞的分析质量保证中，应用本法     

罂粟碱的吸附伏安行为的研究

在ＮＨ３－ＮＨ４Ｃｌ底液中，罂粟碱在汞电极上有一一线性扫描还原峰，峰电位Ｅｐｃ＝－１．４４（ｖｓ．ｓａｔ．Ａｇ／ＡｇＣｌ）。该峰具有明显的吸附性。当ＰＡＰ浓度较小时，扫速较快，搅拌富集时间较长时，电极反应完全为吸附态的ＰＡＰ的还原所控制。     

MgCO3.3H2O水热分解产物及其组成

ＭｇＣＯ_３·３Ｈ_２Ｏ水热分解产物及其组成翟学良，周相廷，李美玲（河北师范大学化学系石家庄０５００１６）关键词ＭｇＣＯ_３·３Ｈ_２Ｏ，Ｍｇ_５（ＣＯ_３）_４（ＯＨ）_２·８Ｈ_２Ｏ，Ｍｇ_５（ＣＯ_３）_４（ＯＨ）_２·５Ｈ_２Ｏ，水热分解，中间体ＭｇＣＯ_...     

Measurement techniques for mercury species in ambient air

This review critically evaluates the measurement methodologies most commonly employed for the analysis of the various forms of mercury (Hg) in air. Emphasis is given to the three most common forms of mercury in air [i.e. gaseous elemental mercury (GEM, Hg⁰), reactive gaseous mercury (RGM), and particle-bound mercury (Hg_p)]. Moreover, we also briefly describe methods dealing with gas-phase analysis of organic mercury species (e.g., mostly methyl mercury), as they are also reported to be present in air on rare occasions. To begin with, we describe the approaches to sampling airborne mercury species and associated sample-treatment strategies. We evaluate both conventional and emerging alternative detection techniques for different mercury forms with respect to their applicability in airborne mercury analysis. We also discuss the artifacts and the biases associated with analysis of different mercury species. Finally, the review summarizes current methodological developments for the determination of mercury in air and highlights future prospects for improvements.     

Polyaniline as a base material for preparation of a mercury standard for use in neutron activation analysis

Polyaniline sorbed with microgram quantity of mercury was prepared and its homogeneity and stability with respect to mercury was evaluated over a period of time. The volatilisation loss of mercury during and after neutron irradiation was studied. It was found that polyaniline was homogeneous and stable with respect to mercury. No loss of mercury from polyaniline was observed during and after neutron irradiation. Thus polyaniline sorbed with mercury can serve as a good standard for neutron activation analysis of mercury.     

The separation of mercury from sea water by adsorption colloid flotation and analysis by flameless atomic absorption

Adsorption colloid flotation has been found capable of separating ionic mercury from sea water quantitatively at levels as low as 0.02 μg l^?1 with use of a cadmium sulfide collector and octadecyltrimethylammonium chloride as the surfactant. The mercury in 25 samples can be separated in 2 h. Following the separation the mercury was analyzed by flameless atomic absorption. Recovery of mercury from 0.5 l samples spiked with 0.010 μg of inorganic mercury gave sol|0.014 ± 0.002 μg/0.5 l. Black Point, Oahu near-shore sea water was found to contain mercury in the range 0.038–0.078 μg l^?1 with no measurable organic mercury fraction. Sea-water samples collected at an open ocean station analyzed for total mercury revealed the highest mercury concentrations above 200 meters. Mercury concentrations in general showed a decreasing trend with increase in depth.     

Peak profile characteristics and atomization mechanisms for selenium in the presence of mercury for graphite furnace atomic absorption spectrometry

Summary Time resolved absorbance profiles, as well as the effects of inorganic acids and mercury salts, have been studied for selenium graphite furnace atomic absorbance signals. Conventional furnace operating procedures and wall atomization were used. Absorbance profiles were found to be sensitive to the mass of the counter ion and mercury present. Negative shifts in the appearance temperature were noted for low levels of mercury salts, whilst the higher levels of mercury caused only slight increasing shifts in the appearance temperature. Peak-area absorbance increases with mercury mass, but a steady-state absorbance was reached above a certain mercury chloride concentration. If mercury is present, a thermal dissociation of a mercury selenium compound is the suggested Se atomization mechanism.     

Rock porosity determination by combination of X-ray computerized tomography with mercury porosimetry

First results are described of coupling of mercury porosimetry with X-ray computerized tomography (CT) as a new combination technique for rock porosity studies. This technique is suitable for rock samples with a pronounced mercury intrusion-extrusion hysteresis and includes CT measurements before and after mercury intrusion. The entrapped portion of mercury, when the pressure after the intrusion into the rock sample is reduced to 0.1 MPa, serves as a contrast agent in the porous network to localize spatial distribution of rock porosity by CT. The results obtained show that the mercury intrusion and therefore the porosity were quite different for the separate mineral phases. Therefore the combination of mercury porosimetry and computer tomography can give 3-D data on mineral-specific porosity distributions with additional pore size information. In contrast to mercury porosimetry as a single method, results of the combination technique with CT represent a direct visualization of porosity variation and do not depend on any special pore network model. Received: 2 July 1996 / Revised: 20 November 1996 / Accepted: 22 November 1996     

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.     

Fractionation studies of mercury in soils and sediments: A review of the chemical reagents used for mercury extraction

Mercury in contaminated soils and sediments could be extracted by various chemical reagents in order to determine the different mercury species and partitions, providing useful information of toxicology, bioavailability and biogeochemical reactivity. Unfortunately, at present, neither specific extractants nor standard protocols exist for the isolation of particular mercury species. Although there has been considerable research focused on reagents for extracting mercury species, there is still little consensus. Thus, workers are advised to select the most appropriate reagent based on the nature of their sample, and to take all possible steps to validate the analyses performed. Therefore, the aim of this paper is to review the current reagents used for determining total mercury and its speciation as well as fractionation such as methylmercury, ethylmercury, elemental mercury, mercury sulphide and organically bound mercury by supposed selective (one reagent) and sequential (several reagents) extractions. The gathering information presented here bring to light the need for standard protocol for which the used chemical reagents should take into account the particular chemistry of mercury associated with specific properties of soil and sediment. Beside this required scheme, appropriate reference materials are also demanded.     

Efficiency of solvent extraction methods for the determination of methyl mercury in forest soils

Methyl mercury was determined by gas chromatography, microwave induced plasma, atomic emission spectrometry (GC-MIP-AES) using two different methods. One was based on extraction of mercury species into toluene, pre-concentration by evaporation and butylation of methyl mercury with a Grignard reagent followed by determination. With the other, methyl mercury was extracted into dichloromethane and back extracted into water followed by in situ ethylation, collection of ethylated mercury species on Tenax and determination. The accuracy of the entire procedure based on butylation was validated for the individual steps involved in the method. Methyl mercury added to various types of soil samples showed an overall average recovery of 87.5%. Reduced recovery was only caused by losses of methyl mercury during extraction into toluene and during pre-concentration by evaporation. The extraction of methyl mercury added to the soil was therefore quantitative. Since it is not possible to directly determine the extraction efficiency of incipient methyl mercury, the extraction efficiency of total mercury with an acidified solution containing CuSO4 and KBr was compared with high-pressure microwave acid digestion. The solvent extraction efficiency was 93%. For the IAEA 356 sediment certified reference material, mercury was less efficiently extracted and determined methyl mercury concentrations were below the certified value. Incomplete extraction could be explained by the presence of a large part of inorganic sulfides, as determined by x-ray absorption near-edge structure spectroscopy (XANES). Analyses of sediment reference material CRM 580 gave results in agreement with the certified value. The butylation method gave a detection limit for methyl mercury of 0.1 ng g(-1), calculated as three times the standard deviation for repeated analysis of soil samples. Lower values were obtained with the ethylation method. The precision, expressed as RSD for concentrations 20 times above the detection limit, was typically 5%.     

Determination of the different states of mercury in seawater near the Vlora and Durres Bays

Because of the toxicity and mobility of organic mercury, there is a need for determination of organic and inorganic mercury at very low concentrations in the environment, especially in seawater. A procedure for extraction and determination of low concentrations of the different states of mercury - total, inorganic, and organic - in seawater, by cold vapour atomic absorption spectroscopy (CVAAS) is described.Inorganic mercury only was directly reduced to the Hg(0) state by tin(II) chloride under strongly acid conditions (H(2)SO(4)) and mercury metal (Hg(0)) was determined by cold vapour atomic absorption spectroscopy. Organic and inorganic mercury were extracted, with toluene, as the bromide derivatives and re-extracted, together, into ammonium chloride solution. Organic mercury was converted into inorganic mercury by thermal digestion at 80-90 degrees C in the presence of strong oxidants. These two states of mercury were determined together as total mercury. Inorganic mercury was measured directly after pre-concentration of the sample by toluene extraction. Toluene dissolved in aqueous phase after re-extraction of the sample was removed by heating for 30 min at 80-90 degrees C. Organic mercury was calculated as the difference between total and inorganic mercury.The sensitivity of the method is 0.0001 ng mL(-1) Hg, depending on sample volume.     

The effects of oxygen on the detection of mercury using laser-induced breakdown spectroscopy

A systematic study of the processes associated with mercury atomic emission in a laser-induced plasma and the interactions of mercury with oxygen species is presented. At early plasma decay times, on the order of 5–10 μs, no significant variation in mercury atomic emission was observed with the addition of oxygen-containing species. At intermediate and long decay times (10–100 μs), a significant reduction in the 253.7-nm mercury emission intensity was recorded with the introduction of oxygen-containing species. The decrease in mercury emission was temporally coincident with the recombination of atomic oxygen, as measured by the O(I) emission. The decreased mercury emission was not due to thermal effects, based on plasma temperature measurements, and was independent of the molecular source of oxygen, for similar concentrations of oxygen as air, carbon dioxide, and carbon monoxide. Analysis of additional mercury atomic emission lines revealed that the reduction in mercury emission in the presence of oxygen species is limited primarily to the 253.7-nm transition. In concert, the data lead to the conclusion that the 253.7-nm mercury emission line is selectively quenched by oxygen species, primarily O₂ and NO, that are formed during the plasma recombination process. Implications for laser-induced breakdown spectroscopy-based emissions monitoring of mercury species are discussed.