溶剂萃取分离测定河水及河流沉积物中As(Ⅲ)As(Ⅴ)、一甲基胂、二甲基胂

砷具有毒性并致癌。不同化学形态的砷,毒性有很大不同。无机三价砷[As(Ⅲ)]的毒性最剧烈,无机五价砷[As(Ⅴ))毒性约为As(Ⅲ)的1%;在水体环境中,还存在一甲基胂酸盐(MMA)和二甲基胂酸盐(DMA),它们的毒性与As(Ⅴ)相仿。水源中的As(Ⅲ),As(Ⅴ)能与其他物质作用形成难溶物而沉     

15种中药材中砷的形态分析

利用高效液相色谱(HPLC)与电感耦合等离子体质谱(ICP-MS)联用技术对6种砷形态[砷胆碱(AsC)、砷甜菜碱(AsB)、三价砷As(Ⅲ)、二甲基砷酸(DMA)、甲基砷酸(MMA)和五价砷As(Ⅴ)]进行了分离,测定了0 ～100 μg/L范围内6种砷形态的混合标准工作曲线,相关系数(r2)优于0.990,方法检出限均为0.2 μg/L.采用甲醇-水(体积比1 : 1)超声法提取了15种中药材中的砷形态,用HPLC-ICP-MS进行分析,结果表明,15种中药材中存在的主要砷形态是有毒的As(Ⅴ),另外还有少量的砷甜菜碱和砷胆碱,并且动物用药中的有机砷含量明显高于植物用药.     

三元杂多蓝(Mo-Bi-P或Mo-Sb-P)光度法测定磷时砷的干扰有何简便的消除方法?

答 :在磷的三元杂多酸形成的条件下 ,砷 (Ⅴ )也同时参与反应对磷的测定造成严重干扰。有人提出用硫代硫酸钠选择性地将砷 (Ⅴ )还原为三价可很简便地消除其干扰[1] 。但在测定钢铁中磷的有时仍出现有结果偏高的现象。最近有报道[2 ] 采用抗坏血酸和硫代硫酸钠的混合溶液作掩蔽剂可有效地消除砷的干扰。该文的作者认为在测定磷的条件下 ,硫代硫酸钠虽能将砷 (Ⅴ )还原为砷 (Ⅲ ) ,但在放置过程中 ,将有部分砷 (Ⅲ )又氧化为砷 (Ⅴ )。十分不利于砷 (Ⅴ )的还原的另一个因素是相当部分的硫代硫酸钠消耗于将试样的基体元素铁 (Ⅲ )还原为铁(Ⅱ…     

高效液相色谱–原子荧光光谱法测定水产品中4种砷形态

建立高效液相色谱–原子荧光光谱法对水产品中4种砷形态[亚砷酸盐As(Ⅲ)、砷酸盐As(Ⅴ)、一甲基砷酸、二甲基砷酸]进行测定。优化后的实验条件:负高压为270 V,灯电流为80 m A,原子化高度为10 mm,硼氢化钾浓度为20 g/L(含5 g/L KOH),载流为体积分数5%的盐酸。方法的线性范围为0~100μg/L,线性相关系数大于0.999。各种砷形态的检出限为0.20~0.45μg/L;测量结果的相对标准偏差为1.98%~4.81%(n=6);加标回收率为88.4%~101.7%。该方法灵敏度高,快速、准确,检测成本低,可用于水产品中砷形态的检测。     

纳米Fe3O4分离富集-悬浮进样-氢化物发生原子荧光法测定砷形态

研究了以纳米Fe3O4为固相吸附剂对痕量无机砷形态的吸附与分离富集,建立了无需洗脱分离的悬浮进样-氢化物发生-原子荧光法测定砷形态的方法。选择的反应体系为0.64 g/L Fe3O4悬浮液-1.0%(m/V)NaBH4溶液-5.0%(V/V)HCl(pH 8),进样5.0 mL时,得到本方法的检出限为13.5 ng/L;As(Ⅲ)浓度在0.05～3.5μg/L范围内呈良好的线性关系;测定0.5μg/L As(Ⅲ)的精密度RSD=3.4%。用国家标准物质GBW10010(大米)验证了本方法测定砷的准确性,测定结果(0.101±0.010μg/g)与标准值(0.102±0.008μg/g)吻合。采用本方法测定了近海海水和雪水样品中的无机砷形态,并进行了加标回收实验。对As(Ⅲ)和As(Ⅴ)的加标回收率在95%～110%之间,结果令人满意。     

高效液相色谱-电感耦合等离子体质谱法测定烟草中砷的形态

应用高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)建立了烟草中As(Ⅲ)、As(V)、一甲基砷酸(MMA)和二甲基砷酸(DMA)4种砷形态的检测方法。研究了不同提取液、提取液体积以及提取时间对提取效果的影响,并对色谱条件进行优化。以15 mL甲醇-水(1∶1)混合液为提取液,30℃超声提取20 min,以(NH4)2HPO4(pH 6.0)为流动相,采用PRP-X100阴离子交换柱对砷形态进行分离。在0.1～25μg/L质量浓度范围内,4种砷形态的线性系数均不小于0.997,日内(n=5)和日间(n=3)RSD均不大于4.2%,仪器检出限为0.1～0.2μg/L,定量下限为0.2～0.5μg/L。在低、中、高3个加标水平下,砷的回收率均为83%～115%,方法稳定性较好,RSD不大于5.7%。采用该方法对国内外8种烟草中的4种砷形态含量进行分析,其含量从高到低依次为As(Ⅴ)、MMA、As(Ⅲ)和DMA。该方法准确、灵敏、方便,适用于烟草中砷形态的测定。     

含砷钢铁中磷砷的吸光光度法联合测定

本法利用磷钼蓝与砷钼蓝吸光度具有加和性的特点,首先利用高酸度提高五价砷的氧化电位,以亚硫酸钠－硫代硫酸钠（双硫）为As(V)及Fe(Ⅲ）的复合还原剂^[1-3],溴化物为还原As(Ⅴ)的动力催化剂^[4],使As(Ⅴ)还原至As(Ⅲ),彻底消除砷的干扰,可测定磷的吸光度^[6],然后,在一般条件测定磷＋砷的吸光度,差量法求得砷的吸光度,最后分别从磷有砷的工作曲线上查出磷和砷的含量。     

微波辅助提取-液相色谱-氢化物发生-原子荧光光谱法分析沉积物中砷的形态

采用微波辅助提取-液相色谱-氢化物发生-原子荧光光谱法(LC-HG-AFS)联用技术分析了太湖沉积物中砷的形态[亚砷酸(As(III))、二甲基砷酸钠(DMA)、一甲基砷酸二钠(MMA)和砷酸As(V)]。测得沉积物中以无机砷为主,且以As(V)居多。选定以1mol/L的磷酸和0.1mol/L抗坏血酸为提取液,在微波辅助萃取(功率为60W,时间12min)下,萃取率达79.84%～91.57%,回收率在94.78%～107.6%之间。4种砷的形态在0～160μg/L之间时线性良好,检测限为0.6～2.3μg/L,相对标准偏差RSD为1.62%～2.20%。方法具有简便、快速、灵敏的特点。     

阴/阳离子交换色谱-电感耦合等离子体质谱法分析鱼和贝类海产品砷的形态

采用阴(Hamilton PRP X100柱)阳(Dionex Ionpac CS- 10柱)离子交换色谱-电感耦合等离子体质谱联用技术,分别以pH 10.3的20 mmol/L NH4HCO3和pH 2.0的5 mmol/L吡啶溶液为流动相,建立了三价砷As(Ⅲ)、五价砷As(V)、一甲基砷酸MMA、二甲基砷酸DMA...     

微波三步提取–高效液相色谱–原子荧光法测定土壤中砷形态

采用高效液相色谱–原子荧光法对土壤中的砷形态进行分析,以了解其对土壤的污染程度。用1 mol/L磷酸–0.5 mol/L抗坏血酸混合提取剂对污染土壤样品进行三步微波提取,用高效液相色谱–原子荧光联用仪测定砷形态含量。As(Ⅲ)和As(V)标准工作曲线的线性范围均为8～100μg/L,线性相关系数(r~2)分别为0.999,0.996,检出限分别为0.11,0.72μg/L。As(Ⅲ),As(V)测定结果的相对标准偏差分别7.6%和9.1%(n=11),加标回收回收率在82.2%～98.3%之间。多数土壤中砷形态以As(V)为主,As(Ⅲ)含量较低。该方法对土壤中的砷提取效果好,测定结果可靠,可为土壤砷污染的修复提供技术支撑。     

微型氢化物发生-原子吸收光谱法测定纺织品中的痕量砷和锑

采用三毛细管微型在线氢化发生技术和装置, 建立了氢化物发生-电热石英管原子吸收法测定纺织品中痕量As、 Sb的分析方法. 研究了共存离子对As、 Sb检测的干扰及消除方法. 结果表明: 该方法除Co、 Sn对As和Ni对Sb有干扰外, 其它干扰元素允许量都较大. 采用酒石酸和KI混合掩蔽剂可抑制Co、 Sn对As和Ni对 Sb的干扰. As和Sb的检出限分别为0.7和0.4 ng/L, 已用于测定纺织品中痕量As和Sb的分析.     

氢化物发生–原子荧光光谱法同时测定锌锭中砷和锑

建立用氢化物发生–原子荧光光度计同时测定锌锭样品中砷和锑含量的方法。采用硝酸一次溶样,加入酒石酸防止锑水解。加入硫脲–抗坏血酸混合溶液作为还原剂和掩蔽剂,消除干扰元素的影响,对实验条件进行了优化。砷和锑的负高压分别为220,200 V,灯电流分别为80,60 mA,还原剂为1%硼氢化钾溶液(含0.5%KOH),载流为10%盐酸溶液,还原时间为30 min。测定砷的线性范围为0~80 ng/mL,相关系数r=0.999 8,检出限为0.35μg/L,测定结果的相对标准偏差为3.18%(n=11);测定锑的线性范围为0~80 ng/mL,相关系数r=0.999 6,检出限为0.42μg/L,测定结果的相对标准偏差为4.32%(n=11),砷和锑的加标回收率在97.46%~100.30%之间。用该方法对标准样品进行测定,测定结果与标准值相符。该方法基体干扰少,灵敏度高,适合于锌锭中砷和锑的日常测定。     

Inter-element interferences in the determination of arsenic and antimony by hydride generation atomic absorption spectrometry with a quartz tube atomizer

The interferences between arsenic and antimony on each other during the hydride generation atomic absorption spectrometry (HGAAS) determination of arsenic and antimony using a quartz tube atomizer (QTA) were examined. In order to eliminate or reduce such interferences by selective heat decomposition of arsine and stibine, a Pyrex adsorption U-tube trap containing glass wool was placed between the drying tube and the quartz tube atomizer. Although at 250 °C stibine decomposes and is held almost completely by the trap, arsine is also decomposed to an extent of 24% and, therefore, thermal decomposition is not useful to eliminate antimony interference on arsenic determination. The effect of coating the glass wool in the U-tube with antimony on the arsenic suppression of the antimony signal was studied. The results showed that the antimony coating in the U-tube could not hold arsenic effectively and its interference on the antimony signal could not be eliminated by this means. In the second part of the study, oxygen was supplied to the quartz tube atomizer during atomization in order to study the effect of supplying oxygen on the antimony signal and on the interference of arsenic in the antimony determination. Sensitivity was increased in the presence of oxygen and interferences of arsenic on antimony determination was decreased by about 10% when oxygen was supplied. It was also observed that the extent of interferences depended mainly on the interferent concentration rather than the analyte concentration.     

离子色谱法测定青霉素残渣中砷的研究

对离子色谱法测定砷及其淋洗条件进行了考察，排除了大量无机阴离子对砷测定的干扰，并应用该法于青霉素残渣中Ａｓ（Ⅴ）的测定。结果表明该法的分离度、重现性、线性响应方面均满足定量分析要求，结果令人满意。     

Speciation analysis of arsenic in samples containing high concentrations of chloride by LC-HG-AFS

Analytical and Bioanalytical Chemistry - Chloride widely exists in the environment and will cause serious interference for arsenic speciation analysis. The determination of four arsenic species...     

Mechanistic study of the aluminum interference in the determination of arsenic by electrothermal atomic absorption spectrometry

The interference effect derived from the presence of aluminum in the wall and platform atomization of arsenic using two sampling modes (aerosol vs. liquid drop) was revisited. The mechanistic action of the Al interference seems to be the result of the formation of some gas phase Al oxide, which would absorb at the arsenic analytical wavelength. A vaporization/condensation process for aluminum oxide seems to exist into the graphite tube with temperature. The effect of protons (as nitric acid) and activated carbon on the behavior of the Al interference was tested. A beneficial effect of overcoming the Al interference was derived from the presence of activated carbon. The mechanistic action of both, protons and activated carbon, was also proposed.     

Determination of arsenic in wheat flour by electrothermal atomic absorption spectrometry using a continuous precipitation-dissolution flow system

A precise, accurate automatic preconcentration method for the determination of total arsenic at the ng g(-1) level in wheat flour is proposed. The sensitivity of the method can be increased by a factor of 20 by precipitating As(V) from 10 ml of digested sample using a weakly acid silver solution. The Ag(3)AsO(4) precipitate is dissolved with 0.5 ml of 6 M ammonia and the resulting solution is collected in an autosampler cup of the ETAAS instrument. The limit of detection achieved in the determination of total arsenic using Pd(NO(3))(2) as modifier is 0.3 ng ml(-1). The proposed method avoids spectral interferences from cations as they do not precipitate with silver cation; anions, which are coprecipitated with silver, are tolerated at concentrations up to about 10 000 times that of As(V). The need to determine As at very low levels in wheat samples, where chloride and phosphate can occur at concentrations 50 000 and 300 000 times higher, respectively, that of arsenic, requires additional steps to suppress the interference of both anions.     

Second-order interference in the neutron activation analysis of arsenic in a germanium matrix

The second-order interference ⁷⁴Ge(n, γ; β^-, n, γ)⁷⁶ As can occur in the activation analysis of arsenic in a germanium matrix, using thermal neutrons. As the literature data show poor agreement, this interference was determined experimentally. A practical formula was derived, for irradiation times longer than 2 h, which showed that the interference, expressed as an apparent arsenic concentration, is proportional to the neutron flux. Experiments were performed for irradiation times of 10, 15 and 20 h at a neutron flux of 10¹⁴ n/cm²/sec, yielding apparent arsenic concentrations in the germanium matrix of respectively 223, 408 and 597 p.p.b. From these results a value of 0.48 ±0.06 barn could be calculated for the activation cross-section of ⁷⁴Ge for neutron capture.     

Investigations of reactions involved in electrothermal atomic absorption procedures : Part 10. Factors Influencing the Determination of Arsenic

Factors of importance for the determination of arsenic by the graphite furnace technique are discussed with special reference to surface reactions. Detailed information with regard to atom formation was obtained by use of an on-line data acquisition system fast enough to monitor signals without distortion. The significance of the surface structure which comes into contact with the sample was assessed by application of the L'vov platform technique. Radioactive measurements showed that losses of arsenic occur even at temperatures as low as 120°C. The different behaviour of γ- and β-radiation was used to study the penetration of arsenic into the graphite. It is shown that arsenic can be stabilized up 1800°C in Standard graphite tubes if an auxiliary oxidizing agent is added. Conditions for stabilization with nickel and lanthanum are also discussed. Reported interference effects caused by chlorine and sulphur were examined experimentally and by use of high-temperature equilibrium calculations. Minimization of interference effects including optimal conditions for atomization are obtained by use of a stabilizing agent in combination with the platform technique.     

氢化物发生电加热石英管原子吸收法测定包头铁矿中的砷、锑、铋

研究了氢化物发生原子吸收法测定包头矿中痕量砷、锑、铋的分析方法,试验确立了反应条件,建立了以KI、抗坏血酸、硫脲为还原体系,消除试样中共存元素的干扰,利用KMnO4消除锑对砷的干扰.砷、锑、铋的检出限可分别达到:0.15,0.28,0.15 ng/mL.方法已用于包头矿分析.