化学蒸气发生-四通道原子荧光光谱法同时测定高纯金中的痕量As,Sb,Bi,Te

采用化学蒸气发生-四通道原子荧光光谱法测定了高纯金中的痕量砷、锑、铋和碲。用乙酸乙脂萃取分离金,水相还原后采用化学蒸气发生-四通道原子荧光光谱法测定高纯金中的痕量砷、锑、铋和碲。在最佳条件下,方法对As,Sb,Bi,Te的检出限分别为0.04,0.05,0.04,0.03 ng/mL(3σ);测定精密度分别为0.98,0.89,0.94,0.99%(对10 ng/mL As,Sb,Bi和Te混合标准,n=7)。方法对实际样品中的As,Sb,Bi,Te进行了同时测定,测定结果与标准方法无明显差异,各元素的加标回收率为95%～105%。     

原子荧光光谱进样技术的研究进展

原子荧光光谱已成为检测金属或类金属的重要手段,其仪器进样方式与所用原子化器类型直接相关。根据进样原理的不同,综述了原子荧光光谱仪器的直接进样、喷雾进样、化学蒸气发生进样和电热蒸发进样4种进样技术,详细介绍了原子荧光光谱各进样技术特别是化学蒸气发生进样和电热蒸发进样的发展历程、原理及优缺点,展望了原子荧光仪器进样技术的发展前景。引用文献75篇。     

氢化物发生-原子荧光光谱法(HG-AFS)测定特硬铅合金中硒和碲

建立了氢化物发生-原子荧光光谱法(HG-AFS)测定特硬铅合金中硒和碲的分析方法。试样经硝酸和酒石酸溶解,硫酸沉淀分离基体铅元素。移取部分试液,在40%盐酸介质中直接用氢化物发生-原子荧光光谱法(HG-AFS)测定样品中的硒;另移取部分试液,加入氢溴酸挥发除去砷、锑、锡、硒等元素,在40%盐酸介质中用氢化物发生-原子荧光光谱法(HG-AFS)测定样品中的碲。考察了测定的最佳条件、铅及共存元素对测定的影响。测定硒和碲的相对标准偏差分别为7.5%～9.3%和3.6%～13.0%,加标回收率分别为88%～92%和98%～102%。准确度和精密度均能满足分析需要,具有较强的实用性。     

原子荧光光谱技术在我国发展及标准化应用现状

简单介绍了原子荧光光谱技术的建立及其在国内的发展历程,重点介绍了蒸气发生-原子荧光光谱(VG-AFS)仪在我国的技术研究、仪器研制及应用;详细总结了蒸气发生-原子荧光光谱(VG-AFS)法在我国标准化方面的研究.我国在多通道原子荧光光谱仪、原子荧光形态分析仪等关键技术及其应用等方面取得了开创性的研究成果,并形成了一系列...     

玩具、铅笔中可溶性砷、锑、硒的形态分析

对玩具、铅笔中可溶性砷、锑、硒的形态分析方法进行了研究,对原子荧光光谱法测定不同价态砷、锑、硒的方法进行了优化,建立了砷、锑、硒的原子荧光光谱形态分析方法。该方法样品加标回收率为82.0%~110.0%,测定结果的相对标准偏差为1.35%~2.22%(n=10)。     

高灵敏度原子荧光光谱系统应用于砷、硒形态分析的研究

将实验室自制的高灵敏度原子荧光光谱系统与色谱分离、在线紫外光前处理装置联用,实现了元素形态的液相色谱分离、在线紫外消解、蒸气发生及原子荧光光谱测定,并以砷、硒两元素为例对系统的分析性能进行研究。样品通过加热混旋提取、离心、过滤,使用反相色谱柱并以5.0 mmol/L磷酸氢二铵缓冲溶液(pH 5.7)-0.5 mmol/L四丁基溴化铵(TBAB)-1%甲醇为流动相进行分离;三价砷(AsO3-3)、二甲基砷(DMA)、一甲基砷(MMA)、五价砷(AsO3-4)可在7 min内进行分离和测定,硒代胱氨酸(SeCys)、硒代蛋氨酸(SeMet)、四价硒(SeO2-3)、六价硒(SeO2-4)的测定约需11 min。在优化实验条件下,方法检出限(DLs,S/N=3)为0.08~0.74μg/L;相对标准偏差(RSD,n=7)为1.4%~7.9%,实际样品的加标回收率为82.5%~116.5%;砷、硒各形态在0.28~40.0μg/L和0.38~80.0μg/L范围内线性良好。建立的联用系统稳定性好、检出限低,可实现样品中低浓度砷、硒形态的准确测定。     

光化学蒸气发生方法用于水样中汞的可视化检测

汞与碘化亚铜的络合显色反应已被广泛应用于汞的可视化检测。然而,样品中高盐、强酸或强碱性的复杂基质对碘化亚铜及络合物的稳定性影响较大,可视化测定受到了严重干扰。光化学蒸气发生是一种绿色、高效的样品引入技术,可实现待测离子与样品基质的有效分离,并且在蒸气发生过程中不需要添加有毒、强还原性试剂。因此,本实验建立了一种光化学蒸气发生和自制碘化亚铜试纸结合用于可视化检测水样中汞的方法,对反应时间、低分子量有机酸浓度等条件进行了考察。在最优的条件下实现了1 ng·mL^-1~1μg·mL^-1浓度范围内水样中汞的可视化半定量分析,并通过原子荧光光谱法对分析结果进行了验证。     

电解冷蒸气发生原子荧光法测定痕量汞

以电解冷蒸气发生技术结合原子荧光光谱仪,采用自行设计的圆盘电解池,进行汞的电解还原冷蒸气发生情况的研究.实验表明,铂作为阴极时,Hg的电化学发生响应信号与化学还原法获得的信号强度相当;同时发现,载气引入位置是影响Hg响应信号强度的重要因素.在1.0 mol/L H2SO4作为阴极液及0.8 A的电解电流条件下,Hg的检出限为1.2 ng/L(3σ); 相对标准偏差为1.7%(n=11).利用此体系分析了标准物质及生物样品中的痕量汞,结果满意.     

氢化物发生-原子荧光光谱法测定高纯阴极铜中硒、碲

本文报道了采用氢化物发生-原子荧光光谱法(HG-AFS)测定高纯阴极铜中硒、碲。实验考察了盐酸、三氯化铁的浓度对氢化物发生效率的影响,探讨了铜和其它共存元素的干扰情况。该法测定硒、碲的检出限分别为0.27μg/L、0.11μg/L,加标回收率分别为94.9%～114.0%、91.8%～105.3%,精密度为1.5%～7.8%。     

路易斯碱对金的化学蒸气发生效率增强的初步研究

提出了某些带有孤对电子的路易斯碱能够增强过渡和贵金属化学蒸气发生(CVG)效率的观点,并使用无色散原子荧光研究乙醚、四氢呋喃和三乙胺对金的CVG效率增强效果进行了验证。研究表明,3种路易斯碱都能使金的荧光信号增强,其增强效果与DDTC相似。在最佳条件下,金的标准校正曲线相关性大于0.99,检出限(3σ)为1μg/L,精密度为5%。     

Proposed reaction mechanisms for selenium UV photolysis vapor generation by computational methods

The production of volatile analyte species by UV photolysis in the presence of low-molecular-weight organic acids as an alternative to chemical vapor generation has been of recent interest. The mechanism of this process is not well understood. Proposed mechanisms often involve photolytic cleavage of the organic acid as the initial step. Evidence suggests that this may not be the dominant route for UV photolysis vapor generation. In this work computational methods were applied to determine a possible alternative mechanism in the absence of free-radical production. The proposed mechanism specifically focused on selenium vapor generation. An energetically favored mechanism was found for UV photolysis of inorganic selenium in the presence of formic and acetic acids which is consistent with previously reported experimental results.     

化学蒸气发生-四通道原子荧光光谱法同时测定水样中的痕量砷、锑、硒和汞

应用自行设计的化学蒸气发生-四通道无色散原子荧光光谱仪,建立了同时测定水样中As、Sb、Se、Hg的新方法.在实验中优化了四元素同时化学蒸气发生条件和测定的最佳工作参数.在样品预处理阶段用HCl将Se6+还原为Se4+,然后用质量浓度5 g/L硫脲将As5+和Sb5+还原为As3+和Sb3+.在最佳条件下,方法对As、Sb、Se、Hg的检出限分别为0.05、0.03、0.05、0.01 ng/mL(3d);RSD分别为0.42%、0.74%、0.97%、1.0%(对5 ng/mL As、Sb、Se和0.5ng/mL Hg混合标准,n=7).用所建立的方法对不同类型水样中的As、Sb、Se、Hg进行了同时测定,测定结果与用标准方法测定所得结果之间无明显差异,各元素的加标回收率在93%～105%.     

Photochemical vapor generation of selenium: Mechanisms and applications

Selenium was the first reported element that could be converted into its volatile compounds via photochemical vapor generation (photo-CVG) process before its atomic spectrometric detection. Photo-CVG is a newly emerging vapor generation technique, offering its inherent advantages of matrix interferences eliminated and high vapor efficiency etc., photo-CVG has been combined with various methods for selenium determination and mechanism exploration. Herein, we summarize the development of selenium in photo-CVG from the first report in 2003, the mechanisms of selenium with or without TiO₂ were discussed and its applications for selenium determination, speciation analysis and prereduction were summarized.     

Preconcentration and in-situ photoreduction of trace selenium using TiO2 nanoparticles, followed by its determination by slurry photochemical vapor generation atomic fluorescence spectrometry

We have developed a method for the determination of trace levels of total selenium in water samples. It integrates preconcentration, in-situ photoreduction and slurry photochemical vapor generation using TiO₂ nanoparticles, and the determination of total selenium by AFS. The Se(IV) and Se(VI) species were adsorbed on a slurry of TiO₂ nanoparticles which then were exposed to UV irradiation in the presence of formic acid to form volatile selenium species. The detection limits were improved 17-fold compared to hydride generation and 56-fold compared to photochemical vapor generation, both without any preconcentration. No significant difference was found in the limits of detection (LODs) for Se(IV) and Se(VI). The LOD is as low as 0.8 ng L^?1, the precision is better than 4.5 % (at a level of 0.1 μg L^?1 of selenium). The method gave good recoveries when applied to the determination of total selenium in a certified tissue reference material (DORM-3) and in spiked drinking water and wastewater samples containing high concentrations of transition and noble metal ions. It also excels by very low LODs, a significant enhancement of sample throughput, reduced reagent consumption and sample loss, and minimal interference by transition and noble metal ions.

Simultaneous determination of arsenic,mercury, antimony and selenium in biological materials with prior collection of gaseous products followed by neutron activation analysis

A method combining prior collection of gaseous products with subsequent neutron activation analysis has been developed for simultaneous determination of traces of arsenic, mercury, antimony and selenium in biological materials. The generation of hydrides of arsenic, antimony and selenium and cold vapor of mercury in the vapor generaion and collection system was investigated by the use of radiotracers of the respective elements. The result indicates that selenium and mercury can be completely evaporated from the digested sample solution in 5M HCl with the addition of 5% sodium tetrahydroborate solution, while additional reduction proces by potassium iodide and ascorbic acid is needed for complete evaporation of arsenic and antimony. The gaseous products were collected in a quartz tube for neutron irradiation. The detection limits of these elements were fount to be in the range of 10^–7 to 10^–8 g under the present experimental conditions. The reliability was checked with NBS standard reference materials.     

Simultaneous determination of arsenic, selenium and mercury in foodstuffs by chemical vapour generation inductively coupled plasma optical emission spectroscopy

A procedure for the simultaneous determination of arsenic, selenium and mercury in foodstuffs has been developed. After a two-step microwave-assisted wet digestion in closed vessels, using concentrated nitric acid and hydrogen peroxide, the solution was analysed by inductively coupled plasma multichannel-based emission spectrometry using chemical vapour generation as the sample introduction system. All steps of the procedure, such as solid sample dissolution, pre-reduction to the suitable oxidation state, vapor generation, transport and atomization have been designed and optimised taking into account the concomitant presence of all the analytes considered. Temporal variation of analytical signals as well as interfering effects due to transition elements were also studied. Under the optimised operating conditions, the achieved detection limits for the simultaneous determination of arsenic, selenium and mercury in foodstuffs were 0.006, 0.023 and 0.018 microg g(-1), respectively, allowing their determination in real samples. Precision of the analytical procedure was 6.8% for arsenic, 5.2% for selenium and 7.7% for mercury (n=7). The accuracy and reliability of the method was verified by the analysis of both standard reference materials (rice flour and spinach leaves) and real samples (natural and Se-enriched rice).     

A new vapor generation system for mercury species based on the UV irradiation of mercaptoethanol used in the determination of total and methyl mercury in environmental and biological samples by atomic fluorescence spectrometry

A new vapor generation system for mercury (Hg) species based on the irradiation of mercaptoethanol (ME) with UV was developed to provide an effective sample introduction unit for atomic fluorescence spectrometry (AFS). Preliminary investigations of the mechanism of this novel vapor generation system were based on GC–MS and FT–IR studies. Under optimum conditions, the limits of determination for inorganic divalence mercury and methyl mercury were 60 and 50 pg mL⁻¹, respectively. Certified reference materials (BCR 463 tuna fish and BCR 580 estuarine sediment) were used to validate this new method, and the results agreed well with certified values. This new system provides an attractive alternative method of chemical vapor generation (CVG) of mercury species compared to other developed CVG systems (for example, the traditional KBH₄/NaOH–acid system). To our knowledge, this is the first systematic report on UV/ME-based Hg species vapor generation and the determination of total and methyl Hg in environmental and biological samples using UV/ME–AFS. Figure A new vapor generation system for mercury species using mercaptoethanol under UV irradiation was developed as an effective sample introduction unit for atomic fluorescence spectrometry     

Determination of mercury(II) ion by electrochemical cold vapor generation atomic absorption spectrometry.

A technique for determination of mercury is described; it is based on electrolytic reduction of Hg(II) ion on a graphite cathode, the trapping of mercury vapor and its volatilization into a quartz tube aligned in the optical path of an atomic absorption spectrometer. The electrochemical cell consisted of a graphite cathode and an anode operating with constant direct current for the production of mercury atoms. A pre-activated graphite rod was used as the cathode material. The optimum conditions for electrochemical generation of mercury cold vapor (the electrolysis time and current, the flow rate, the type of electrode and electrolyte) were investigated. The characteristic electrochemical data with chemical cold vapor using NaBH4-acid were compared. The presence of cadmium(II), arsenic(III), antimony(III), selenium(IV), bismuth(III), silver(I), lead(II), lithium(I), sodium(I) and potassium(I) showed interference effects which were eliminated by suitable separation techniques. The calibration curve is linear over the range of 5-90 ng ml(-1) mercury(II). The detection limit is 2 ng ml(-1) of Hg(II) and the RSD is 2.5% (n = 10) for 40 ng ml(-1). The accuracy and recovery of the method were investigated by analyzing spiked tap water and river water.     

Organic,inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry

A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L^− 1 KBr in 6 mol L^− 1 HCl) was added to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L^− 1 HCl and 2.5% m/v NaBH₄ solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 °C and the atomization temperature was set at 650 °C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g^− 1 for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.