应用AFS—930型双道原子荧光光度计联合测定水中的砷和硒

本文采用原子荧光光谱法,研究了联合测定水样中砷和硒的技术。用10%盐酸和1%硫脲-1%抗坏血酸混合试剂处理样品,并以2.0%硼氢化钾和0.5%氢氧化钠为还原剂,在5%的盐酸介质测定砷和硒。砷和硒的检出限分别为:0.20μg/L和0.13μg/L,本方法具有操作简便、快速、基体干扰少、灵敏度高等优点,可用于水样中砷和硒的联合测定。     

氢化物—原子荧光法测定饮用水中砷的方法研究与改进

应用氢化物—原子荧光法测定生活饮用水中的砷含量,实验过程中发现绘制的标准曲线和已知浓度水样的测定结果均存在较大误差,通过分析确定起还原剂和掩蔽作用的抗坏血酸在测定过程中存在干扰。在改进方法后,只用硫脲作为还原剂和稳定剂而不加抗坏血酸后测定的标准曲线的线性相关系数为0.9997、检出限为0.035μg/mL,用砷标准溶液6.00μg/L的浓度测得相对标准偏差RSD=2.67%,加标回收率为96.5%-102.5%。实际水样的测定结果也符合国家标准。证明该改进方法对于测定低含量砷且杂质离子未达到影响结果测定浓度时的水样具有过程简单、可靠性强的优点。     

氢化物发生-原子吸收法测定水中砷

本文采用氢化物发生-原子吸收法测定环境水样中砷的含量,最低检出限为0.20μg/l,对不同的水样进行测定,回收率在97.6％～103.0％之间。方法灵敏度高,基体干扰少,操作简便,易推广。     

微波消解-原子荧光法测定食品中的砷

目的:建立测定食品中砷的微波消解原子荧光法。方法:采用微波消解处理样品,原子荧光法分析测定。结果:砷标准系列浓度在(0~8.0)ng/ml范围内线性关系良好。本方法检出限为0.11 ng/ml样品中砷回收率为88.0%~93.2%,具有简便、快速、灵敏、准确的特点。结论:本方法测定结果令人满意,具有一定的实用价值。     

氢化物原子荧光光谱法同时测定生活饮用水中砷和硒

建立了氢化物发生原子荧光光谱法同时测定生活饮用水中砷和硒的方法.测试结果表明砷和硒在质量浓度分别为0.00μg/L~10.00μg/L和0.00μg/L~40.00μg/L范围内呈线性关系,相关系数分别为(砷r=0.9998,硒r=0.9997)。仪器检出限为砷:0.03μg/L硒:0.05μg/L。本方法检出限砷为0.075μg/L;硒为0.125μg/L。水质样品中砷的回收率为92.6%~96.5%,精密度为0.8%~1.4%;硒的回收率为91.2%~97.4%,精密度为1.0%~1.6%。应用本方法测定生活饮用水中的砷和硒方法简便、快速,结果准确可靠,较好地提高了工作效率。     

原子荧光光谱法测定地表水中的砷

砷是水质监测常规项目,是我国实施排放总量控制的主要指标之一,具有致突变、致癌和致畸变作用。根据AFS-230E原子荧光光度计测定原理及方法,来测定地表水中的砷。结果表明:线性关系良好,相关系数0.9999,检出限为0.018μg·L~(-1),相对标准偏差为0.6%,标准样品测定结果符合要求,实际水样测定加标回收率为94%-102%,比较试验结果无显著性差异。该法试剂用量少,实现自动进样,特别适合大批量样品测定,值得推广使用。     

阳极溶出伏安法水体镉污染快速测定方法研究

建立一种快速测定水体中镉、铅、汞、砷的阳极溶出伏安法。对现场快速测定影响因素进行探讨,并主要对镉的检出限、精密度和准确度进行研究,将该方法运用到广西龙江镉污染事故应急监测中,并与多种其他方法进行比对。结果表明:该方法运用最优温度为5~40℃,水样最佳p H范围为4~9。便携式阳极溶出伏安法测定污染水样中的镉,检出限为0.1μg/L,加标回收率在80%~110%间;在实际样品质量浓度在2~110μg/L范围内准确度均满足要求,实际样品测定精密度2%~5%;与在线监测结果的相对偏差≤4%,与石墨炉原子吸收测定结果相对偏差≤1%。该方法稳定、快速,灵敏度高,准确度好,可广泛用于重金属污染事故应急监测。     

火焰原子吸收分光光度法测定环境水样中钾和钠

采用火焰原子吸收分光光度法测定环境水样中钾和钠的含量,通过对不同波长条件下钾钠吸光度的比较,选择出最佳灵敏线应用于本机分析试验,过程简单,效果十分理想。方法灵敏度高、线性关系良好、结果准确稳定,检出限钾为0.005mg/L、钠为0.008mg/L。应用此方法测定2种水样中的钾和钠,相对标准偏差1.2%～1.9%,回收率95.2%～103.2%。     

紫外分光光度法测定金精矿中砷量

采用硝酸-硫酸消解样品,二乙基二硫代氨基甲酸银分光光度法测定金精矿中砷量。考察了碘化钾、二氯化锡、无砷锌粒和铜试剂银盐三氯甲烷加入量对砷量测定的影响。该法经国家标准样品验证,获得满意结果,与金精矿国家标准方法比对良好。方法检出限为0.014μg/mL,测定结果的相对标准偏差(RSD,n=11)为4.15%～7.17%,准确度0.58%～5.57%,方法测定范围为0.050%～0.35%。     

电感耦合等离子体原子发射光谱法同时测定生铁中硅锰磷砷锑锡

本文研究了电感耦合等离子体原子发射光谱法(ICP-OES)同时测定生铁中常量元素磷、锰、硅及痕量元素砷、锑、锡。用盐酸-硝酸混合酸溶解试样,选择了各元素的合适分析谱线,在最佳工作条件下,测得磷、锰、硅、砷、锑、锡的检出限分别为0.0042%、0.0003%、0.0009%、0.0024%、0.0033%、0.0021%,相对标准偏差(n=10):常量元素磷、锰、硅及痕量元素砷的RSD小于2%,痕量元素锑和锡的RSD小于10%。本方法用标准物质进行测定,测定结果与认定值吻合。     

石墨炉原子吸收法测定洗涤剂中砷含量

建立了石墨炉原子吸收光谱法测定洗涤剂中砷含量的方法。采取硝酸及高氯酸法处理样品,加入基体改进剂硝酸镍,应用石墨炉原子吸收光谱法测定砷。结果表明,测定一次回归方程为Y=0.0012X+0.0009,相关系数r=0.9994。检出限为0.16 ug/L,回收率为92.9%～101.4%,相对标准偏差为1.42%～3.18%。该方法具有快速、准确、灵敏度高等优点,适用于洗涤剂中砷含量的检测。     

微波消解-氢化物发生原子荧光光谱法同时测定蔬菜中汞、砷

本文建立了一种梯度升压微波消解样品,氢化物发生双道原子荧光光谱法同时测定蔬菜样品中汞、砷的方法。在优化实验条件下,蔬菜样品中Hg、As回收率分别为98.9%-109.3%和91.1%-96.1%;检出限分别为0.0094μg/L、0.0331μg/L。并对其相讨标准偏差(RSD)、精密度和准确度进行了评估,结果表明该方法用于蔬菜中Hg、As的同时测定是可行的。     

Liquid-vapor equilibria in the AsCl3-HCl-H2O system

The liquid-vapor equilibria in the AsCl₃-HCl-H₂O system have been studied by a flow method at high hydrogen chloride concentrations (above 20 wt %) over the entire arsenic trichloride solubility range at temperatures from 25 to 105°C and a pressure of 1.013 MPa. The composition effects on the parameters of the liquid-vapor equilibria have been assessed, and the conditions for the most effective recovery of arsenic trichloride from hydrochloric acid solutions by distillation were established.     

Characterization of arsenic (V) and arsenic (III) in water samples using ammonium molybdate and estimation by graphite furnace atomic absorption spectroscopy

Arsenic (V) is known to form heteropolyacid with ammonium molybdate in acidic aqueous solutions, which can be quantitatively extracted into certain organic solvents. In the present work, 12-molybdoarsenic acid extracted in butan-1-ol is used for quantification of As (V). Total arsenic is estimated by converting arsenic (III) to arsenic (V) by digesting samples with concentrated nitric acid before extraction. Concentration of As (III) in the sample solutions could be calculated by the difference in total arsenic and arsenic (V). The characterization of arsenic was carried out by GFAAS using Pd as modifier. Optimization of the experimental conditions and instrumental parameters was investigated in detail. Recoveries of (90-110%) were obtained in the spiked samples. The detection limit was 0.2 microg l(-1). The proposed method was successfully applied for the determination of trace amount of arsenic (III) and arsenic (V) in process water samples.     

氢化物发生-原子荧光光谱法测定土壤砷的国内研究进展

氢化物发生-原子荧光光谱法(HG-AFS)是目前测定可形成氢化物、气态化合物痕量元素的重要分析技术.本文综述了近年来周内HG-AFS法与不同的消解提取方法结合,或与其他分析仪器联用,测定土壤中总砷、无机砷、不同价态砷及砷形态分析的方法.     

流动注射-氢化物发生-ICP-AES法检测痕量的砷

本文用流动注射,氢化物发生-ICP-AES检测体系对小麦粉、煤灰和土壤等样品中痕量的砷的进行检测,采用正交设计试验找出仪器测定的最佳工作条件,并对影响测定的主要参数和砷的氢化物产生条件进行了研究。该方法对试样中砷的检测结果令人满意,砷检测限为0.15μg/L,相对标准偏差<2.5%。     

Spectrophotometric determination of trace arsenic in water samples using a nanoparticle of ethyl violet with a molybdate-iodine tetrachloride complex as a probe for molybdoarsenate

A new spectrophotometric method was developed for the determination of low ppb levels of arsenic in water. We found that Ethyl Violet with molybdate-iodine tetrachloride complex forms nanoparticles under acidic conditions, which provide a sensitive probe for molybdoarsenate. The nanoparticles form stable particles with a diameter micrometers in size in the presence of heteropolyacid, and the resulting particles give a purple color to the apparently homogeneous solution, the intensity of which depends on the arsenic concentration. The nanoparticle itself is unstable due to conversion of the dye to a colorless carbinol species under acidic conditions without heteropolyacid. Although triphenylmethane dyes have been the subject of a number of investigations, there do not appear to be any reports on the dye particles for trace determination. The calibration curve is linear up to 20 microg L-1 arsenic, and the detection limit is 0.5 microg L-1 (6.6 x 10(-9) mol L-1). The coefficient of variation for spectrophotometry at 10 microg L-1 is 5.8% (n = 8). Furthermore, it is possible to detect concentrations as low as 1 microg L-1 arsenic visually using this method. The interferences from phosphorus and silica were eliminated using an anion exchange column and sodium fluoride as a masking agent, respectively. The proposed method has been successfully applied to water samples in abandoned mine water, groundwater, and river water. There was good agreement between the results obtained by the proposed method and those by hydride generation atomic absorption spectrometry. Since this method is specific for As(V), it is applicable to the speciation of arsenic oxidation states. Our method has enormous practical potential for simple and field detection of arsenic, requiring no complex apparatus or skilled laboratory support.     

Investigation of biomethylation of arsenic and tellurium during composting

Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species. Extraordinary high concentrations of up to 150 mg kg(-1) methylated arsenic species as well as conversion rates up to 50% for arsenic and 5% for tellurium were observed. In contrast, little to no conversion was observed for antimony, tin and germanium. In addition to experiments with metal(loid) salts, composting of arsenic hyperaccumulating ferns Pteris vittata and P. cretica grown on As-amended soils was studied. Arsenic accumulated in the fronds was efficiently methylated resulting in up to 8 mg kg(-1) methylated arsenic species. Overall, these studies indicate that metal(loid)s can undergo intensive biomethylation during composting. Due to the high mobility of methylated species this process needs to be considered in organic waste treatment of metal(loid) contaminated waste materials.     

Liquid chromatography online with selected reaction monitoring electrospray mass spectrometry for the determination of organoarsenic species in crude extracts of marine reference materials

The large number of arsenic species known to be present in marine samples and their broad range of chemical properties pose a significant challenge for arsenic speciation analysis. The predominantly used ICPMS detection online with HPLC only provides element-selective information, which is not sufficient for the identification of arsenic species without standards. However, electrospray tandem mass spectrometry in the selected reaction monitoring (SRM) mode enables molecule-selective detection with high sensitivity for quantification. A new HPLC-ES-SRM method was developed for the determination of more than 20 organoarsenic species. Two chromatographic systems were compared, an anion exchange method and a combined cation anion exchange method. Collision-induced dissociation breakdown curves were constructed for all arsenic species investigated and used to optimize the SRM conditions. External calibration was performed with mixed standard solutions containing 21 arsenic species. Two SRM transitions were monitored for most of the analytes, and their intensity ratio was used for quality control. The developed methods were applied for the quantification of arsenic species in extracts of four marine reference materials. Spiking experiments revealed, especially for the early-eluting analytes on the anion exchange system, significant signal suppression by coeluting matrix constituents. Therefore, the standard addition approach was used for quantification. AsB, the major arsenic species in tuna CRM 627 and DORM-2, was accurately quantified with the combined cation anion exchange ES-SRM method.     

Determination of arsenic compounds by high-performance liquid chromatography-ultrasonic nebulizer-high power nitrogen-microwave-induced plasma mass spectrometry: an accepted coupling

To establish a sensitive, accurate, and precise determination of arsenic compounds, a high power nitrogen microwave-induced plasma (1.3 kW) mass spectrometer (N2-MIP-MS) has been successfully coupled with an ultrasonic nebulizer (HPLC-USN) that is attached to a high-performance liquid chromatograph. It is examined as an element-specific detector for its applicability to the optimization and determination of seven arsenic compounds [arsenic acid, methylarsonic acid (MA), dimethylarsinic acid (DMA), arsenobetaine (AB), arsenocholine (AC), trimethylarsine oxide (TMAO), and tetramethylarsonium ion (CMI)]. This HPLC-USN-MIP-MS coupling is an encouraging combination as an alternative method for mass spectroscopy for elemental speciation analysis. Interchanging of the MIP-MS fabricated nebulizer (concentric) with an ultrasonic nebulizer, increases 3-6 times the ion signals for the anionic and 6-12 times those for the cationic arsenic compounds as compared to traditional methods. The HPLC-USN-MIP-MS combination used is excellent, amplifying the ion signals about 1.5-2 times for cationic and 1.3-2.8 times for the anionic arsenic compounds as compared to the HPLC-ICPMS coupling. The detection limits for As(V), MA, DMA, AB, TMAO, AC, and TMI (in Milli-Q-water) obtained with the optimized HPLC-USN-N2-MIP-MS system are 0.46, 0.36, 0.73, 0.21, 3.64, 0.39, and 0.32 microg L(-1), respectively, about 13-50 times lower than the HPLC-MIP-MS and about 3-11 times lower than the HPLC-ICPMS. The detection limits of As(V), MA, DMA, AB, TMAO, AC, and TMI, which spike in the urine, are deteriorated by 1.7-4.2 times compared with the detection limits of the seven different As compounds, which are prepared in the Milli-Q-water. The repeatability (RSD for three successive analyses) and reproducibility (RSD for three successive analyses performed on three different days), considering peak area and peak height, achieved for seven different arsenic compounds are 0.5-7 and 0.7-8%, comparable with the HPLC-ICPMS (0.3-8.5%; 4-12%) and HPLC-MIP-MS (0.4-9%; 5-12%) systems. The combined HPLC-USN-N2-MIP-MS has been adequately applied to the determination of AB in NIES Candidate Human Urine CRM. The results agree with the HPLC-ICPMS values. Chloride interference as 40Ar35Cl+ is not found in the urine and with the high chloride matrix (10000 mg L(-1)).