南通地区地下水中砷的形态分布特征研究

2012年开展南通市1∶50000水文地质调查，对监测网内地下水进行采样分析，建立了基于液相色谱－电感耦合等离子体质谱联用测定地下水中砷形态的方法，该方法检出限为0．1μg／L。样品分析表明，南通地区地下水中砷的形态以三价无机砷为主，有机砷以砷胆碱（AsB）和乙基砷（DMA）为主，样品中未检出五价无机砷。通过砷形态研究表明，南通近海地区地下水中砷的质量浓度较低（＜0．5μg／L），主要以 As（Ⅲ）为主，不存在其他砷的形态；近长江地区地下水中砷的质量浓度较高（＞1．0μg／L），砷形态以 As（Ⅲ）和 DMA为主。     

茶叶中的微量砷及其在茶汤中形态的分析

采用电感耦合等离子体发射光谱（ＩＣＰ－ＡＥＳ）对茶叶中微量砷进行了测定，并结合离子交换和溶剂萃取技术对茶汤中的砷的形态化合物进行了分离和测定。     

L-半胱氨酸对氢化物发生原子吸收法测定砷增强信号作用的研究

将生化试剂Ｌ－半胱氨酸用于砷氢化物发生体系，在ｐＨ１．７～２．０，Ｌ－半胱氨酸用量大于１．５ｍ ｇ／ｍ ｌ时，Ｌ－半胱氨酸的存在使砷信号增强最大，该条件下使砷检出限低了２．６ 倍，水样加标加收率为９６％ ～９８．８％ ，应用于自来水和地表水中痕量砷的测定，获得了满意的结果。     

分光光度法测定地面水Cr^6＋的改进

分光光度法测定地面水中Ｃｒ６＋,一般都采用锌盐沉淀分离以除去水样中悬浮物和色度。分析中加入９ｍｏｌ／Ｌ硫酸和７ｍｏｌ／Ｌ磷酸及显色剂３种溶液,比色测定。几年来,在测定中发现锌盐沉淀处理水样仍有一定的色度;加入３种溶液显色对测定来说也不够简便。为此,进...     

ICP- AES法测定防腐处理后木材中可溶性铜铬砷

采用电感耦合等离子发射光谱法同时测定防腐处理后木材中可溶性铜、铬、砷，优化了试验条件，确定了最佳分析线。方法在0.500mg／L—10.0mg／L范围内线性良好，铜、铬、砷的检出限分别为0.003mg／L、0.01mg／L、0.07mg／L.木材样品平行测定的RSD为0.5％—1.2％，加标回收率为97.0％—102％，与原子吸收光谱法的测定结果相吻合。     

砷钼杂多酸—罗丹明6G荧光猝灭法测定痕量砷

探讨了在聚乙烯醇存在下，砷钼杂多酸－罗丹明６Ｇ荧光猝灭法测定痕量砷的条件，其λｃｍ位于５６０ｎｍ，Ａｓ（Ｖ）量在２～６０ｎｇ／ｍＬ范围内与荧光猝灭值成线性关系，方法可用于环境水样中痕量砷的测定。     

高效液相色谱法在无机分析中的应用

本文综述了高效液相色谱法在无机分析中的应用进展。分别介绍了正相、反相、离子对、离子交换、排阻和胶束流动相等液相色谱法在有机金属化合物、金属络合物、无机阳离子和阴离子分离及测定上的实际应用。     

砷钼杂多酸─罗丹明6G荧光猝灭法测定痕量砷

探讨了在聚乙烯醇存在下，砷钼杂多酸──罗丹明６Ｇ荧光猝灭法测定痕量砷的条件，其λ_（ｅｍ）位于５６０ｎｍ，Ａｓ（Ｖ）量在２～６０ｎｇ／ｍＬ范围内与荧光猝灭值成线性关系。方法可用于环境水样中痕量砷的测定。     

氢化物发生—原子荧光法测定水中砷（Ⅲ）,砷（V）

以吡咯烷二硫代氨基甲酸铵（ＡＰＤＣ）络合砷（Ⅲ），氯仿萃取，用湿消化法处理萃取液，消除有机物质干扰，所得消化样品用氢化物发生－原子荧光测定砷（Ⅲ）。在水样中加入碘化钾还原砷（Ｖ）至砷（Ⅲ），用相同方法测定总量。总量减去砷（Ⅲ）量，求得砷（Ｖ）含量。     

CL-5209微色谱柱分离富集光度法测定环境样品中微量铀

研究了ＣＬ５２０９萃淋树酯微色谱柱柱性能以及对铀和主要伴生元素的分离富集情况。结果表明，在１ｍｏｌ／Ｌ硝酸介质中，除铀（Ⅵ）、钍（Ⅳ）、金（Ⅲ）和少量稀土元素能被ＣＬ５２０９萃淋树酯吸附外，其它常见共存元素不被吸附。用５ｍｌ１ｍｏｌ／Ｌ的ＨＮＯ３可以安全淋洗除去钍和少量稀土，再用１４ｍｌ混合掩蔽剂可以完全解析铀，结合以在溴代十六烷基吡啶存在下５Ｂｒ－ＰＡＤＡＰ显色，能快速准确地测定环境样品中ｐｐｂ级铀     

高效液相色谱-原子荧光光谱联用分析土壤中形态砷

采用高效液相色谱(HPLC)-原子荧光光谱(AFS)联用技术分析土壤中亚砷酸盐[As(Ⅲ)]、二甲基砷(DMA)、一甲基砷(MMA)和砷酸盐[As(Ⅴ)]等4种形态砷,以磷酸为提取剂、抗坏血酸为还原剂,优化了水浴提取条件。As(Ⅲ)、DMA、MMA和As(Ⅴ)在7 min之内实现了完全分离,在1.00μg/L～100μg/L范围内线性良好,实验室检出限分别为0.25μg/L、0.36μg/L、0.39μg/L和0.51μg/L,土壤标准样品平行测定的RSD≤7.4%,加标回收率为79.5%～95.0%,提取率为74.6%～90.4%。     

硫化物水样预处理方法的改进

以2% NaOH 溶液替代醋酸锌溶液为硫化物吸收液;另由体积分数50%的盐酸替代磷酸作酸化剂,可避免吸收瓶壁附着物生成,提高硫化物的吸收率,样品加标回收率为92.5%～100%.     

高效液相色谱-原子荧光光谱联用测定水中形态砷

采用高效液相色谱-氢化物发生-原子荧光光谱联用技术测定水中亚砷酸盐[As(Ⅲ)]、二甲基砷(DMA)、一甲基砷(MMA)和砷酸盐[As(V)]等4种形态砷,以磷酸盐缓冲溶液为流动相,硼氢化钾为还原剂,优化了仪器主要技术参数.As(Ⅲ)、DMA、MMA和As(V)在7 min内实现了良好的基线分离,在5.00 μg/L～...     

Preservation of sulfidic waters containing dissolved As(III)

Solutions containing variable concentrations of sulfide (0 to 31 ppm) and arsenite (0.35 to 10 ppm) were subjected to several different preservation treatments. As predicted by equilibrium thermodynamics, at near-neutral pH the experimental solutions were undersaturated with respect to orpiment (As2S3). However, upon acidification to pH 2 with HCl or HNO3, instantaneous precipitation of poorly crystalline As2S3 occurred in sulfidic solutions which resulted in the loss of dissolved arsenite. These results have implications concerning the practice of acidifying water samples containing hydrogen sulfide with HCl or HNO3 for the purpose of preserving total arsenic values. If a near-neutral water sample contains 1 ppm arsenite and as little as 0.4 ppm sulfide, loss of dissolved arsenic will occur upon acidification. An alternative three-step preservation method involving base addition, oxidation, and acidification is proposed and investigated as an appropriate technique for preserving sulfide-bearing aqueous samples for total arsenic.     

Fractionation of sedimentary arsenic from Port Kembla Harbour, NSW, Australia

The binding of arsenic in sediments of the heavily industrialised Port Kembla Harbour, NSW, Australia, has been investigated. Both dredge and core samples have been used to develop a sieving/sequential extraction (SE) procedure. Dredge samples included oxic surficial and deeper anoxic sediment. The main core sample analysed was 18 cm deep, sliced at 2 cm intervals. Sediment was sieved to three size ranges (<63 microm, 63-250 microm, >250 microm) and each of these was then subjected to a four step SE, sequentially solubilizing arsenic as ion exchangeable, 1 M HCl soluble, NH(2)OH.HCl soluble, and strong oxidising acid soluble. Concentrations of 50-500 mg As kg(-1) were found, elevated well above local background values. The core sample showed elevated concentrations of arsenic within the top 6-8 cm (300-500 mg As kg(-1)), relative to the deeper sediment (100-200 mg As kg(-1)). Substantial portions of the total arsenic present in the 0-8 cm sediments of core and dredge samples, were found to be soluble in 1 M pH 5 phosphate buffer or 1 M HCl. Arsenic in the lower 8-18 cm of the core displayed different solubility, the fourth stage SE strong acid digestion being required to solubilize >90% of the deep sediment arsenic. It appears that diagenesis had resulted in remobilisation of weakly bound arsenic with subsequent diffusion and deposition in surficial layers. Strong acid soluble arsenic present in deeper sediments has two possible origins: sedimented as strongly bound remaining untouched by diagenetic events, or subjected to diagenetic reactions such as pyritization, which lead to more stable crystalline forms of minerals.     

Arsenic-speciation in arsenate-resistant and non-resistant populations of the earthworm,Lumbricus rubellus

Arsenic speciation was determined in Lumbricus rubellus Hoffmeister from arsenic-contaminated mine spoil sites and an uncontaminated site using HPLC-MS, HPLC-ICP-MS and XAS. It was previously demonstrated that L. rubellus from mine soils were more arsenate resistant than from the uncontaminated site and we wished to investigate if arsenic speciation had a role in this resistance. Earthworms from contaminated sites had considerably higher arsenic body burdens (maximum 1,358 mg As kg-1) compared to the uncontaminated site (maximum 13 mg As kg-1). The only organo-arsenic species found in methanol/water extracts for all earthworm populations was arsenobetaine, quantified using both HPLC-MS and HPLC-ICP-MS. Arsenobetaine concentrations were high in L. rubellus from the uncontaminated site when concentrations were expressed as a percentage of the total arsenic burden (23% mean), but earthworms from the contaminated sites with relatively low arsenic burdens also had these high levels of arsenobetaine (17% mean). As arsenic body burden increased, the percentage of arsenobetaine present decreased in a dose dependent manner, although its absolute concentration rose with increasing arsenic burden. The origin of this arsenobetaine is discussed. XAS analysis of arsenic mine L. rubellus showed that arsenic was primarily present as As(III) co-ordinated with sulfur (30% approx.), with some As(v) with oxygen (5%). Spectra for As(III) complexed with glutathione gave a very good fit to the spectra obtained for the earthworms, suggesting a role for sulfur co-ordination in arsenic metabolism at higher earthworm arsenic burdens. It is also possible that the disintegration of As(III)-S complexes may have taken place due to (a) processing of the sample, (b) storage of the extract or (c) HPLC anion exchange. HPLC-ICP-MS analysis of methanol extracts showed the presence of arsenite and arsenate, suggesting that these sulfur complexes disintegrate on extraction. The role of arsenic speciation in the resistance of L. rubellus to arsenate is considered.     

Monitoring of arsenic in aquatic plants, water, and sediment of wastewater treatment ponds at the Mae Moh Lignite power plant, Thailand

Mae Moh is a risky area for arsenic contamination caused by the effluent from biowetland ponds in Mae Moh lignite-fuelled power plant. The objective of this study was to investigate the arsenic concentrations of Mae Moh biowetland ponds and determine the main factors which are important for arsenic phytoremediation in the treatment system. The result revealed that arsenic concentrations in the supernant were in the range of less than 1.0 μg As L^???1 to 2.0 μg As L^???1 while those in the sediment were in the range of 25–200 μg As kg soil^???1. Both values were below the Thailand national standard of 0.25 mg As L^???1 for water and 27 mg As kg soil^???1 for the soil. Arsenic accumulation in the biomass of 5 aquatic plants at the biowetland ponds ranged from 123.83 to 280.53 mg As kgPlant^???1. Regarding the result of regression analysis (R ²?= 0.474 to 0.954), high concentrations of organic matter and other soluble ions as well as high pH value in the sediment could significantly enhance the removal of soluble arsenic in the wetland ponds. From the regression equation of accumulated arsenic concentration in each aquatic plant, Eichhornia crassipes (Mart.) Solms. (R ²?= 0.954), Ipomoea aquatica Forsk. (R ²?= 0.850), and Typha angustifolia (L.) (R ²?= 0.841) were found to be preferable arsenic removers for wastewater treatment pond in the condition of low Eh value and high content of solid phase EC and phosphorus. On the other hand, Canna glauca (L.) (R ²?= 0.749) appeared to be favorable arsenic accumulator for the treatment pond in the condition of high Eh value and high concentration of soluble EC.     

微波消解-氢化物发生原子荧光光度法 测定土壤中的砷

建立了微波消解一氢化物发生原子荧光光度法测定土壤中砷的方法。对微波消解条件进行了优化，用5mL硝酸和2mL过氧化氢的混合酸作消解溶剂，在设定的微波条件下砷提取完全。用5％的盐酸作为反应载流，12g／L硼氢化钾与0．5％氢氧化钠的混合液为还原剂，直接定容后应用HG．AFS测定，并通过测定国家标准参考物质和加标回收实验，对方法进行了验证。实际土壤加标同收率97％～103％。     

Speciation of arsenic using solid phase extraction cartridges

Various solid phase extraction (SPE) cartridges were investigated for speciation of arsenite [As(III)], arsenate [As(v)], monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Cartridges containing different types of sorbent materials were tested for arsenic retention and elution characteristics. Alumina cartridges were found to completely retain all the four target arsenic species, and are suitable for removal and preconcentration purposes. For speciation analysis, different arsenic species were separated on the basis of their selective retention on and elution from specific cartridges. DMA was retained on a resin-based strong cation exchange cartridge and eluted with 1.0 M HCl. MMA and As(v) were both retained on a silica-based strong anion exchange cartridge and sequentially eluted with 60 mM acetic acid (for MMA) and 1.0 M HCl [for As(v)]. As(III) was not retained on either cartridge and remained in solution. Arsenic species in solution and those eluted from the cartridges were subsequently quantified by using flow injection with hydride generation atomic fluorescence spectrometry (FI-HGAFS) and hydride generation atomic absorption spectrometry (FI-HGAAS). A detection limit of 0.05 microg L(-1) arsenic in water sample was achieved using HGAFS. An application of the method was demonstrated at a drinking water treatment facility. As(III) and As(v) species were determined in water at various stages of treatment. The method is suitable for routine determination of trace levels of arsenic in drinking water to comply with more stringent environmental regulations.     

The impact of a rice based diet on urinary arsenic

Rice is elevated in arsenic (As) compared to other staple grains. The Bangladeshi community living in the United Kingdom (UK) has a ca. 30-fold higher consumption of rice than white Caucasians. In order to assess the impact of this difference in rice consumption, urinary arsenicals of 49 volunteers in the UK (Bangladeshi n = 37; white Caucasians n = 12) were monitored along with dietary habits. Total urinary arsenic (As(t)) and speciation analysis for dimethylarsinic acid (DMA), monomethylarsonic acid (MA) and inorganic arsenic (iAs) was conducted. Although no significant difference was found for As(t) (median: Bangladeshis 28.4 μg L(-1)) and white Caucasians (20.6 μg L(-1)), the sum of medians of DMA, MA and iAs for the Bangladeshi group was found to be over 3-fold higher (17.9 μg L(-1)) than for the Caucasians (3.50 μg L(-1)). Urinary DMA was significantly higher (p < 0.001) in the UK Bangladeshis (median: 16.9 μg DMA L(-1)) than in the white Caucasians (3.16 μg DMA L(-1)) as well as iAs (p < 0.001) with a median of 0.630 μg iAs L(-1) for Bangladeshi and 0.250 μg iAs L(-1) for Caucasians. Cationic compounds were significantly lower in the Bangladeshis (2.93 μg L(-1)) than in Caucasians (14.9 μg L(-1)). The higher DMA and iAs levels in the Bangladeshis are mainly the result of higher rice consumption: arsenic is speciated in rice as both iAs and DMA, and iAs can be metabolized, through MA, to DMA by humans. This study shows that a higher dietary intake of DMA alters the DMA/MA ratio in urine. Consequently, DMA/MA ratio as an indication of methylation capacity in populations consuming large quantities of rice should be applied with caution since variation in the quantity and type of rice eaten may alter this ratio.