偶合反应流动注射化学发光法测定汞

基于Hg(Ⅱ)置换Fe(Ⅱ)-DETA配合物中的Fe(Ⅱ)和Fe(Ⅱ)-鲁米诺-溶解氧产生化学发光的反应,建立了置换偶合反应,流动注射化学发光测定痕量汞的新方法.方法线性范围为1×10~(-7)～1×10~(-5)g·ml~(-1)相对标准偏差为3.5%(n=11,C=1×10~(-6)g·ml~(-1)),检出限为3×10~(-8)g·ml~(-1),方法用于工业废水中汞的测定,结果令人满意.     

汞—溴—亚甲蓝三元体系萃取光度法测定香烟中微量汞

亚甲蓝(MB)是一种本身摩尔吸光率很高的有机碱性显色剂,在金属光度分析中已有广泛应用。利用该显色剂建立的测定金、硼、钯等的光度分析方法已见报道,但未见用于测定汞的报道。为此,本文系统地研究了汞-溴-亚甲蓝的形成及萃取条件。并建立了测定香烟中微量汞的方法,该方法快速,选择性好,灵敏度高。 1 试验部分 1.1 仪器与试剂 岛津UV-265型分光光度计 pHS-29A型酸度计(上海第二分析仪器厂) 汞标准溶液:称取氯化汞(汞量大于99.5％)0.2715g于1L棕色量瓶中,用硫酸(1mol·L~(-1))溶解并稀至刻度。摇匀。该液含汞1×10~(-3)mol·L~(-1)。使用时配成1×10~(-5)mol·L~(-1)汞标准液(供当日使用)。     

基于Schiff-base结构化合物载体的汞离子选择性电极的制备与表征

高产率合成了一种新的Schiff-base结构化合物,并将其表征为高选择性聚合物膜汞离子选择性电极载体。考察了不同增塑剂及离子交换剂对膜电极响应性能的影响,在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1.0×10-6~3.0×10-4mol/L,响应斜率为(29.3±0.3)mV/dec,检出限为2.6×10-7mol/L;该电极响应速率快(小于12 s),可在较宽的pH范围内(pH2.8~5.6)使用,且其它常见碱金属、碱土金属以及过渡金属离子对该测试电极的干扰小;可准确检测自来水中汞离子的浓度。     

抑制荧光光谱法测定模拟废水中痕量汞

基于在pH 8.00磷酸氢二钠-柠檬酸缓冲介质中,血红蛋白对过氧化氢氧化对甲酚反应具有强的催化作用,汞(Ⅱ)对上述指示反应具有灵敏的抑制作用,从而提出了抑制荧光光谱法测定模拟废水中汞含量的方法。优化的试验条件如下:①血红蛋白的浓度为2.00×10-7 mol·L-1;②对甲酚的浓度为1.60×10-3 mol·L-1;③过氧化氢的浓度为1.11×10-3 mol·L-1;④反应时间为80min。在激发波长318nm、发射波长405nm处,反应体系的ΔF(即F0与F值之差)与汞(Ⅱ)的浓度在2.00×10-8～1.00×10-5 mol·L-1范围内呈线性关系。方法用于模拟废水的分析,测得加标回收率在94.0%～105%之间,相对标准偏差(n=8)在2.5%～3.3%之间。     

原子荧光光谱法快速测定锑矿石中的汞、铋、硒

用王水直接水浴分解样品,硝酸、高氯酸湿法消解,酒石酸掩蔽锑,应用氢化物发生-原子荧光光谱法(HG-AFS)不经分离直接测定锑矿石中微量杂质元素汞、铋、硒的含量。汞、铋、硒的标准系列浓度分别在0.000 0~0.006 0、0.000~0.060、0.000~0.010 mg/L范围内与荧光强度具有良好的线性关系,线性相关系数分别为1.000 0、0.999 9、0.999 8,其加标回收率分别为95%~102%、99%~102%、99%~105%。相对标准偏差分别为0.82%~1.1%、1.1%~6.4%、1.6%~2.1%(n=8)。该方法对汞、铋、硒的检出限分别为2.0×10-11、4.1×10-11、4.0×10-10g/mL。     

环糊精敏化光度法测定废水中痕量汞(Ⅱ)

利用汞(Ⅱ)在β-环糊精存在下与镉试剂1B的显色反应,提出了测量痕量汞的新方法。在pH 10的硼砂缓冲溶液、0.01%Triton X-100和0.001 mol/Lβ-环糊精(-βCD)的存在下,镉试剂1B-汞(Ⅱ)在波长495 nm处有最大吸收,其吸光度与0~2μg/10mL范围内的Hg(Ⅱ)呈线性关系,表观摩尔吸光系数为6.75×105L.mol-1.cm-1。本法灵敏度高、选择性较好,可用于废水中痕量汞的测定。     

活性炭富集测定天然水中超痕量汞

天然水中汞含量极低,即使采用十分灵敏的定量技术,也需经较大倍数的富集才可准确测定.活性炭对汞吸附力极强,能从锌盐或金盐溶液中定量吸附低达1×10~（-9）g·L~(-1)的汞.在前文工作基础之上,我们进一步研究了汞在活性炭上的吸附行为和解吸附条件,建立了一种定量富集水中超痕量汞的技术,用于河水等实际样品测定,获得了满意结果.     

催化分光加入标准法测定废水中痕量汞的研究

研究催化分光光度法测定水中痕量汞(Ⅱ)的各种干扰因素及消除方法.建立用于测定多组分共存水样中痕量汞(Ⅱ)的催化分光光度加入标准法.以催化分光光度加入标准法测定废水中痕量汞(Ⅱ),其线性范围为3.0×10-3~8.0×10-2mg/L,加标回收率97.79%~102.78%,相对标准偏差(RSD)为0.116%,测定结果与原子吸收光谱法相同.     

汞-邻菲啰啉-刚果红缔合体系光度法测定痕量汞

在含有汞(Ⅱ)试液中,先后加入乙酸-乙酸钠缓冲溶液(pH 5.7)、1.0×10-3mol.L-1邻菲啰啉溶液0.8 mL、4.0×10-4mol.L-1刚果红溶液1.2 mL及10 g.L-1阿拉伯树胶(GA)溶液0.8 mL使反应生成汞与邻菲啰啉和刚果红的络合物。在此缔合体系中,GA对显色反应兼有增敏和增稳作用。汞(Ⅱ)质量浓度在1.0 mg.L-1范围内与其吸光度呈线性关系。反应体系的吸收峰位于540 nm波长处,在此波长条件下测定其表观摩尔吸光系数为8.49×104L.mol-1.cm-1。此方法已应用于测定河水中汞量,求得相对标准偏差(n=5)小于2.0%,平均回收率为100.4%。     

基于Schiff-base结构化合物载体的汞离子选择性电极的制备与表征

高产率合成了一种新的Schiff-base结构化合物,并将其表征为高选择性聚合物膜汞离子选择性电极载体.考察了不同增塑剂及离子交换剂对膜电极响应性能的影响,在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1.0×10-6 ～3.0×10-4 mol/L,响应斜率为(29.3±0.3) mV/dec,检出限为2.6×...     

Speciation of mercury by ion chromatography with post-column derivatization

The chromatographic behaviour of Hg(II), methylmercury, phenylmercury and Cu(II) on three different sorbents, strong acidic sulfobutyl cation-exchanger, weak basic aminopropyl anion-exchanger and silicagel has been studied. A dithizone solution in cetyltrimethylammonium hydrogensulfate water micellar medium was found as a useful post-column derivatization reagent for UV-VIS detection. The detection limits 1.1 ng, 2.2 ng, 6.2 ng and 1.6 ng were found in silicagel chromatographic system and dithizone detection system for Hg(II), methylmercury, phenylmercury and respectively for Cu(II).     

Low level mercury analysis by neutron activation analysis

During the years 1974–77 about 200 low level mercury analyses on samples with less than 1000 ng Hg/kg were made at the Danish Isotope Centre. This paper describes our method of neutron activation analysis for low level mercury analysis. The accuracy of the mercury analyses is shown by the results of the determinations on NBS standard, SRM 1642, and on intercalibration analyses. The accuracy found is better than 10% for samples with about 100–300 ng Hg/kg and better than 10 ng Hg/kg for samples with less than 100 ng Hg/kg. The limit of detection for the analyses is about 1–5 ng Hg/kg, depending on the sample and the exact method of analysis. The lowest standard deviations on duplicate analyses are about 1 ng Hg/kg. The general level found in sea water is about 10 ng Hg/kg, in ground water about 50 ng Hg/kg, and in rain water about 100 ng Hg/kg.     

Untersuchung von systematischen Fehlern bei der Bestimmung von Hg-Gesamtgehalten im Bereich < 10?5% in anorganischen und organischen Matrices mit zwei unabh?ngigen Verbundverfahren

Zusammenfassung Systematische Fehler, die bei der Bestimmung von Hg im ng/g und pg/g-Bereich vor allem bei der Probennahme, Probenvorbereitung und beim Probenaufschluß auftreten, wurden mit ²⁰³Hg Radiotracertechniken und mit zwei für den Spurenbereich entwickelten Verbundverfahren untersucht. Beim emissionsspektrometrischen Verfahren (OES-MIP) wird die Probe im mikrowelleninduzierten Sauerstoff Plasma (MIP) verascht und das Hg nach Abtrennung mit einem Au-Absorber in einem Argon-Plasma angeregt. Das emittierte Hg-Licht wird mit einer Photodiode registriert. Nachweisgrenze: 0,01 ng Hg; Variationskoeffizient: 5% für 1 ng Hg. Beim zweiten Verfahren wird Hg nach dem Probenaufschluß (HClO₃/HNO₃) mit einem mechanisierten Aufschlußsystem nach der Kalt-Dampf-Technik (Ascorbinsäure/SnCl₂ bzw. NaBH₄) freigesetzt, an einem Gold-Absorber gesammelt und anschließend durch flammenlose AAS bei 253,7 nm bestimmt. Nachweisgrenze: 0,5 ng Hg; Variationskoeffizient: 5% für 5 ng Hg.

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Study of systematic errors in the determination of total Hg levels in the range < 10^–5% in inorganic and organic matrices with two reliable spectrometrical determination procedures

Summary In the determination of Hg at ng/g and pg/g levels systematic errors are due to faults in the analytical methods such as intake, preparation and decomposition of a sample. The sources of these errors have been studied both with ²⁰³Hg-radiotracer techniques and two multi-stage procedures developed for the determination of trace levels. The emission spectrometric (OES-MIP) procedure includes incineration of the sample in a microwave induced oxygen plasma (MIP), the isolation and enrichment on a gold absorbent and its excitation in an argon plasma (MIP). The emitted Hg-radiation (253,7 nm) is evaluated photometrically with a semiconductor element. The detection limit of the OES-MIP procedure was found to be 0,01 ng, the coefficient of variation 5% for 1 ng Hg. The second procedure combines a semi-automated wet digestion method (HClO₃/HNO₃) with a reduction-aeration (ascorbic acid/SnCl₂), and the flameless atomic absorption technique (253,7 nm). The detection limit of this procedure was found to be 0,5 ng, the coefficient of variation 5% for 5 ng Hg.

Wir danken der Deutschen Forschungsgemeinschaft Bonn-Bad Godesberg für Personal- und Sachmittel, Herrn Professor Dr. E. Schlichting, Universität Hohenheim für Bodenproben und wertvolle Diskussionen, der Firma Kalle, Wiesbaden, für die Bereitstellung von Kunststoff-Folien sowie Fräulein R. Kolb für ihre Hilfe bei der Durchführung dieser Arbeit.     

Ultra-trace determination of mercury in river waters after online UV digestion of humic matter

A fully automated online ultraviolet (UV) digestion method for subsequent mercury (Hg) quantification in humic matter containing river waters is reported. The new developed flow injection analysis system (FIAS) consists basically of a UV lamp, a meander-form quartz glass reaction tube for online irradiation of the sample, and a nano-gold collector for preconcentration of dissolved mercury species. The FIAS is coupled to an atomic fluorescence spectrometer (AFS) for Hg detection. The optimized procedure allows accurate mercury quantification in water samples with up to 15 mg CL(-1) as dissolved organic carbon by addition of only 1% (v/v) of hydrogen peroxide solution and online UV irradiation for 6 min. Addition of strong oxidants and any other reagents is avoided due to the use of the catalytic active nano-gold collector. Here, preconcentration of Hg species, release of mercury as Hg(0), and AFS measurement are performed without addition of any reagents. Hence, the proposed approach offers significant advantages over existing methods. Analytical figures of merit showed the good performance of the developed method: The limit of quantification was found to be as low as 0.14 ng Hg L(-1). The linear working range is from 0.1 to 200 ng Hg L(-1) and relative standard deviation is <6.0% (n = 9). The system was successfully validated by comparison of the mercury concentrations found in model and real water samples obtained by the reference method EPA 1631 and the proposed method. Furthermore, application to six real river waters confirmed the feasibility of the proposed approach.     

Certification of total mercury and methylmercury concentrations in mussel homogenate (Mytilus edulis) reference material, IAEA-142

Due to the increased demand for new reference materials certified for total and methylmercury (MeHg) a sample of mussel homogenate (IAEA-142) has been prepared. Thirteen experienced laboratories reported results for total Hg of which 9 laboratories also reported results for MeHg content. Laboratories reporting MeHg results used various isolation techniques (solvent extraction, saponification, acid leaching, ion-exchange separation, and distillation) and detection systems (cold vapour atomic absorption spectrometry (CV AAS), cold vapour atomic fluorescence spectrometry (CV AFS), gas chromatography with electron capture detector (GC/ECD) and HPLC with CV AAS detector). In the case of total Hg, most of the laboratories used acid digestion, only two used alkaline dissolution, followed either by CV AAS or CV AFS. One laboratory used neutron activation analyses with radiochemical separation. The data received were in good agreement. The value for total Hg was certified to be 126 ng/g, with a 95% confidence interval from 119 to 132 ng/g. For MeHg the certified value of 47 ng/g expressed as Hg was assigned, with a 95% confidence interval from 43 to 51 ng/g. Stability testing has shown that both total and MeHg are stable if samples are stored in a dry and dark place at room temperature. The sample is now available as a certified reference material and is, in particular, useful for quality control measurements of Hg and MeHg in mussel samples at low concentration levels.     

Renewable Copper and Silver Amalgam Film Electrodes of Prolonged Application for the Determination of Elemental Sulfur Using Stripping Voltammetry

New, renewable copper (Hg(Cu)FE) and silver (Hg(Ag)FE) based amalgam film electrodes applied for the determination of elemental sulfur using differential pulse cathodic stripping voltammetry are presented. With surface areas adjustable from 1 to 12 mm², both electrodes are characterized by very good surface reproducibility (≤2%) and long‐term stability (a few thousand measurement cycles). The mechanical refreshing of the amalgam film takes about 1–2 seconds. The effects of various factors such as instrumental parameters and the supporting electrolyte composition were optimized. Interferences from sulfides are easily removed by the addition of acid, and bubbling with argon, for Hg(Ag)FE. In the case of Hg(Cu)FE, sulfides did not interfere. The calibration graph is linear within the studied range from 16 ng L^?1 to 4.8 μg L^?1 for Hg(Cu)FE, and up to 6.4 μg L^?1 for Hg(Ag)FE (t_acc=15 s). The correlation coefficients for the two electrodes were at least 0.997. The detection limits for a low concentration of S(0) and t_acc=60 s are as low as 14 ng L^?1 for Hg(Cu)FE and 4 ng L^?1 for Hg(Ag)FE. The proposed method was successfully applied and validated by studying the recovery of S(0) from spiked river water.     

Certification of total mercury and methylmercury concentrations in mussel homogenate (Mytilus edulis) reference material, IAEA-142

Due to the increased demand for new reference materials certified for total and methylmercury (MeHg) a sample of mussel homogenate (IAEA-142) has been prepared. Thirteen experienced laboratories reported results for total Hg of which 9 laboratories also reported results for MeHg content. Laboratories reporting MeHg results used various isolation techniques (solvent extraction, saponification, acid leaching, ion-exchange separation, and distillation) and detection systems (cold vapour atomic absorption spectrometry (CV AAS), cold vapour atomic fluorescence spectrometry (CV AFS), gas chromatography with electron capture detector (GC/ECD) and HPLC with CV AAS detector). In the case of total Hg, most of the laboratories used acid digestion, only two used alkaline dissolution, followed either by CV AAS or CV AFS. One laboratory used neutron activation analyses with radiochemical separation. The data received were in good agreement. The value for total Hg was certified to be 126 ng/g, with a 95% confidence interval from 119 to 132 ng/g. For MeHg the certified value of 47 ng/g expressed as Hg was assigned, with a 95% confidence interval from 43 to 51 ng/g. Stability testing has shown that both total and MeHg are stable if samples are stored in a dry and dark place at room temperature. The sample is now available as a certified reference material and is, in particular, useful for quality control measurements of Hg and MeHg in mussel samples at low concentration levels. Received: 24 September 1996 / Revised: 20 November 1996 / Accepted: 8 December 1996     

Ion-chromatographic trace analysis of mercury, cadmium and zinc by post-column derivatisation with a water-soluble porphyrin

Summary A post-column derivatisation system with mesotetra (4-sulfonatophenyl)-porphyrin (TPPS₄) and PAR as accelerating agent in a borate buffer pH 11.5 in the presence of tartrate and NaCl is proposed. The complexes of Cd, Zn and Hg have maximum absorption at 430 nm. The separation system consists of silica-gel chemically bonded cation exchanger as stationary phase and a tartrate-NaCl solution as mobile phase. The separation can be finished within 10 min. The calibration curves of these metal ions with the peak area of the chromatogram were found to be linear in the range of 0.002–0.8, 0.1–8.0 and 0.05–20.0 mg/l for Cd, Hg and Zn. The detection limits for Cd, Hg and Zn are 0.05, 5 and 1 ng. This new method was applied to the analysis of waste water, silicates and corn with satisfying results.

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Ionen-chromatographische Spurenanalyse von Hg, Cd und Zn durch Nachsäulen-Derivatisierung mit einem wasserlöslichen Porphyrin

     

Mercury speciation by coupling cold vapour atomic absorption spectrometry with flow injection on-line preconcentration and liquid chromatographic separation

A fully automated system for the direct determination of methylmercury (MeHg), ethylmercury (EtHg), phenylmercury (PhHg), and inorganic mercury (Hg(II)) at the ng/L level is described. It is based on solid phase extraction preconcentration incorporated in a flow injection (FI) system, high performance liquid chromatography (HPLC) separation, reduction combined with thermolysis and determination by cold vapour atomic absorption spectrometry (CVAAS). For preconcentration a microcolumn of bonded silica with octadecyl functional groups (C18 reversed phase material) was used as a sorbent for the mercury complexes formed on-line with ammonium pyrrolidine dithiocarbamate. Retained mercury species are eluted with a methanol-acetonitrile-water mixture and subjected to separation on an octadecylsilane (ODS) column before determination by CVAAS. The sensitivity of organo-mercury determination could be improved by using NaBH₄ as a reductant combined with a thermolysis step. In order to perform on-line measurements the preconcentration microcolumn was mounted in a pressure-tight casing. Limits of detection for MeHg, EtHg, PhHg and Hg(II) employing a sample volume of 58.5 mL were 9, 6, 10 and 5 ng/L, respectively. The relative standard deviation (RSD) calculated from 9 repeated measurements was found to be 3.6%, 5.5%, 10.4% and 7.6% for MeHg, EtHg, PhHg and Hg(II), respectively. Finally, the application of this method for speciation of mercury in fish and human urine is described.     

Mercury speciation by coupling cold vapour atomic absorption spectrometry with flow injection on-line preconcentration and liquid chromatographic separation

A fully automated system for the direct determination of methylmercury (MeHg), ethylmercury (EtHg), phenylmercury (PhHg), and inorganic mercury (Hg(II)) at the ng/L level is described. It is based on solid phase extraction preconcentration incorporated in a flow injection (FI) system, high performance liquid chromatography (HPLC) separation, reduction combined with thermolysis and determination by cold vapour atomic absorption spectrometry (CVAAS). For preconcentration a microcolumn of bonded silica with octadecyl functional groups (C18 reversed phase material) was used as a sorbent for the mercury complexes formed on-line with ammonium pyrrolidine dithiocarbamate. Retained mercury species are eluted with a methanol-acetonitrile-water mixture and subjected to separation on an octadecylsilane (ODS) column before determination by CVAAS. The sensitivity of organo-mercury determination could be improved by using NaBH₄ as a reductant combined with a thermolysis step. In order to perform on-line measurements the preconcentration microcolumn was mounted in a pressure-tight casing. Limits of detection for MeHg, EtHg, PhHg and Hg(II) employing a sample volume of 58.5 mL were 9, 6, 10 and 5 ng/L, respectively. The relative standard deviation (RSD) calculated from 9 repeated measurements was found to be 3.6%, 5.5%, 10.4% and 7.6% for MeHg, EtHg, PhHg and Hg(II), respectively. Finally, the application of this method for speciation of mercury in fish and human urine is described. Received: 10 March 1997 / Revised: 29 January 1998 / Accepted: 5 February 1998