Determination of total arsenic by photo-decomposition of organoarsenic compounds and hydride generation electrothermal atomic absorption spectrometry

A method was developed for the determination of total arsenic concentration in less than ng/ml level by decomposition of organoarsenicals using photo -oxidation combined with in situ trapping of arsenic hydride on a palladium coated graphite tube with subsequent atomization and detection by AAS. The organoarsenicals include monomethylarsenic, dimethylarsenic, arsenobetaine, arsenocholine, o -aminobenzenarsenate and p -aminobenzenarsenate. The method is simple and sensitive. Detection limit was obtained from different arsenic compounds over the range from 0. 058 to 0.063 ng/ml as As (based on three times of the standard deviation of 10 blank measurements) and the relative standard deviations for ten replicate measurements were from 2.0 to 3.8%. The calibration curves of arsenic compounds including inorganic and organic arsenicals were linear over the range from 0.1 to 3.0 ng/ml as As. The recommended method has been applied to the determination of total arsenic in tap and lake water samples at ng/ml levels.

Determination of Trace Germanium in Marine Sediments by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS)

A method for the analysis of trace germanium in marine sediments by HG-AFS has been investigated. The experimental conditions such as the acidity of reduction reaction, the amount of sodium boro-hydride, the carrier gas flow rate, etc., were tested and optimized by using a kind of orthogonal design. The detection limit of the presented method is 0.95 μg L -1 for germanium. The calibration curve shows a satisfactory line in the concentration range 0-320 μg L -1 Ge with a variation coefficient of ±2.1%.

Effect of sample treatment on determination of arsenic （Ⅲ） and arsenic （Ⅴ） in aqueous and tissue samples by hydride generation atomic absorption spectrometry

The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic （Ⅲ） and arsenic （Ⅴ） in biological and environmental samples. The method is based on hydride generation and atomic absorption spectrometry. For both As （Ⅲ） and As （Ⅴ） the parameters such as NaBH4, HCI concentration, and pH were optimized. Absorption signal of As （Ⅴ） was approximately 17% of As （Ⅲ） signal. Therefore, for estimation of As （Ⅲ） and As （Ⅴ） concentrations in various samples the difference between the absorbance obtained for arsenic, without and with previous treatment of samples with potassium iodide （KI）, can be applied. The calibration graphs were linear （r〉0.99）, and the detection limits of the method based on three times the standard deviation of the blank were 0.14 and 0.64 μL^-1 for As （Ⅲ） and As （Ⅴ）, respectively. The relative standard deviation （R.S.D.） of measurements was less than 10%. As a means of checking performance method, water samples were spiked with known concentrations of both As （Ⅲ） and As （Ⅴ）, and recovery above 94% was obtained. The proposed method was applied successfully to determine inorganic As （Ⅲ） and As （Ⅴ） in various environmental and total As in biological samples.

Determination of Selenium in Marine Aquatic Products by Hydride Generation-atomic Fluorescence Spectrometry (HG-AFS)

A method for the analysis of selenium in marine aquatic products by HG-AFS has been investigated. The method is based on the reduction of inorganic selenium to volatile SeH2 which is bubbled out by carrier gas of pure argon, and then swept to Ar-H2 flame quarts atomizer to measure its fluorescence intensity. The hydride generation, transportation, atomization and some instrumental parameters were studied by a kind of orthogonal design. The optimum conditions selected are as follows： reactive acidity, 20% HC1; the amount of NaBH4, 4.9mL; gas flow of argon, 600mLmin^-1; atomizing temperature, 200 ℃ ; negative high voltage, - 300V; light current, 100 mA; integral time, 7s. The detection limit of the presented method is 0.072μgL^-1 for selenium. The calibration curve shows a satisfactory line inthe concentration range from 0.000 to 1.000μgL^-1 Se. The recovery is 95.8%-102.2%.

DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

Microwave Digestion Sample Hydride Generation-Atomic Fluorescence Spectrometry Determines Trace Selenium of Mogroside

0.2000g mogroside sample is digested by 7.0ml nitric acid and 3.0ml hydrogen peroxide, and generated by coprecipitation enrichment hydride - atomic fluorescence spectrometry determines trace selenium in it. Under optimum experiment conditions, a standard curve was produced using selenium standard solution, the linear equation is Ise=2890.6c＋0.0012,compared wish the linear relaticnship is not by coprecipitation direct determination of standard series Ise=82.56c＋0.0018 Selenium detection sensitivity was increased by 35.01 times,the correlation coefficient of obtained linear regression equation is 0.9996, the detection limit is 0.0012~tg/L and the relative standard deviation is 0.76% （n=5）. Containing 0.1808pg.g-1 Se Luo Han Shen samples. Based on mogroside sample, add a certain of standard solution to do recovery experiment, the obtained recovery rate is in 95.8%-103.6% and the result is satisfactory.

Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry （EcHG-AAS） with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As（Ⅲ） shows significantly higher absorbance at low electrolytic currents than As（Ⅴ） in 0.3 mol·L^-1 H2SO4. The electrolytic current used for the determination of As（Ⅲ） without considerable interferences of As（Ⅴ） was 0.4 A, whereas the current for the determination of As（Ⅲ） and As（Ⅴ） was 1.2 A. For equal concentrations of As（Ⅲ） and As（Ⅴ） in a sample, the interferences of As（Ⅴ） during the As（Ⅲ） determination were smaller than 5%. The absorbance for As（Ⅴ） could be calculated by subtracting that for As（Ⅲ） measured at 0.4 A from the total absorbance for As（Ⅲ） and As（Ⅴ） measured at 1.2 A, and then the concentration of As（Ⅴ） can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·mL^-1 for As（Ⅲ） and As（Ⅴ）, respectively. The relative standard deviations were of 3.5% for 20 ng·mL^-1 As（Ⅲ） and 3.2% for 20 ng·mL^-1 As（Ⅴ）. The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

原子吸收法测定菠菜中砷的质量分数不确定度评定

依据微波消解氢化物发生原子吸收法测定菠菜中砷的质量分数,对检测过程中的样品称量、定容、消解后测定的质量浓度、仪器、标准物质、移液器、重复性等不确定度的分量进行分析。参考CNAS—GL06:2006《化学分析中不确定度的评估指南》和JJF 1059.1—2012《测量不确定度评定与表示》计算合成不确定度和扩展不确定度。质量浓度和重复性是影响砷结果准确性的关键因素,质量浓度引入的不确定度占比为6.09%,重复性引入的不确定度占比为1.79%,该评定可以为氢化物发生原子吸收法测定菠菜中砷质量分数的不确定度评定提供参考。

氢化物发生辅助雾化火焰原子吸收法测定水中铅

研究了一种提高火焰原子吸收测定铅灵敏度的新方法———氢化物发生辅助雾化的火焰原子吸收法;方法采用硼氢化钠与铅(Ⅳ)在原火焰原子吸收雾化器喷口处反应生成氢化物,以提高火焰原子吸收法的雾化效率;采用重铬酸钾-酒石酸预处理体系,重铬酸钾氧化样品中铅(Ⅱ)为铅(Ⅳ),酒石酸稳定铅(Ⅳ)的亚稳态化合物;对各种实验参数和干扰情况也进行了研究;方法操作简单、快速,灵敏度比通常的火焰原子吸收法提高了6.8倍;检出限(K＝3,n＝11)为6.64μg／L,线性范围为0.021～3.2mg／L;测定水样的回收率达94%～99%。

氢化物发生-原子吸收光谱法测定中药中砷(Ⅲ)和砷(Ⅴ)

本文用氢化物发生(HG) 原子吸收光谱法(AAS)测定中药中的三价砷及五价砷。在pH5.6～6.0时,砷(Ⅲ)与硼氢化钾作用生成气态氢化物,而砷(Ⅴ)不发生反应;在2mol/L盐酸溶液中,用硫脲和抗坏血酸还原砷(Ⅴ)为砷(Ⅲ),同法测总砷,用差减法求得砷(Ⅴ)含量。方法检出限为7.5μg/L,RSD为1.45%。回收率为89.2%～114.6%。利用本方法成功地对六种中成药中的砷进行了形态分析。

氢化物发生-原子吸收光谱法测定磷矿石中砷

研究了用氢化物发生原子吸收光谱法测定磷矿石中微量砷，考察了还原掩蔽剂种类、还原剂用量、载气流速的影响。结果表明：以硫脲-抗坏血酸-酒石酸混合溶液作还原剂还原效果好，同时还能掩蔽各种干扰离子；该还原剂用量为2mL，载气流速为1.0L／min；吸光度与砷含量在0-20μg／L范围内呈线性关系，检出限为0.032μg／L。此法可用于磷矿石中砷含量的测定，相对标准偏差小于0．5％，回收率为97.5％-101.4％。

微型氢化物发生原子吸收光谱法测定砂岩铀矿中微量硒

利用三毛细管微型在线氢化发生技术和装置,研究了微型氢化物发生AAS测定砂岩铀矿中微量硒的分析方法。着重研究了共存离子对硒的干扰影响。结果表明该方法除Cu2+有干扰外,其它干扰元素允许量都较大。采用Fe3+可抑制Cu2+的干扰,结果令人满意。该方法灵敏度高,干扰少,硒的检出限为0.9μg/L,操作简单、快速、试剂消耗少,样品分析精密度RSD=2.4%,是一种测定砂岩铀矿中微量硒的好方法。

顺序注射氢化物发生原子吸收法测定砷

通过在气液分离器的液体出口处增置微型电磁阀 ,延长样品和还原剂NaBH4在气液分离器中的反应时间 ,实现了单注射泵顺序注射 氢化物发生原子吸收法测定砷。本法自动化程度高 ,分析速度 112次 /h ,样品消耗量为 0 .4mL ;4 μg/LAs测定 10次的相对标准偏差为 2 .0 % ;检出限 0 .0 9μg/L。用于标样中砷的测定 ,结果满意。

有机酸在重铬酸钾铅烷发生体系中的作用

研究了铅烷发生体系有机酸的作用.结果显示:在K_2Cr_2O_7-无机酸体系中氧化剂的还原产物Cr(Ⅲ)对铅烷的发生的抑制是单独使用K_2Cr_2O_7效率不高的原因;体系中加入有机酸的主要作用是掩蔽Cr(Ⅲ),消除其抑制作用.

用流动注射氢化物原子吸收法测定土壤中的砷和沉积物中的汞

在选择了样品最佳消化方法、砷化氢和汞蒸气生成及检测最佳条件的基础上,将流动注射与氢化物原子吸收光谱法相结合,建立了土壤中砷和沉积物中汞质量浓度的测定方法.结果表明,流动注射氢化物原子吸收法测定土壤中砷的检出限为2 ng/L,精密度为1.36%-5.08%,准确度为93.6%-106.1%.测定沉积物中汞的检出限为3 ng/L,精密度为0.97%-5.53%,准确度为93.2%-109.6%.流动注射氢化物原子吸收法简便、快速,分析精密度和准确度均满足环境样品的分析测试要求,可以用于土壤中砷和沉积物中汞的测定.

贵州万山汞矿地区人发中汞的含量及其赋存状态的XAFS原位研究

利用氢化物发生—原子荧光法测定了贵州万山汞矿地区人发中汞的含量。结果发现,该地区从事汞制剂操作的一线工人及居民的头发中汞含量远超过世界其它各地,其平均值为837 μg/g,说明该地区受污染状况非常严重。通过XAFS法测试了3组汞含量较高的头发样品。由XANES谱得出,虽然3组头发中汞的含量不同,但其中汞离子的价态是一致的。比较样品与参考样品的EXAFS谱得出,虽然3组头发样品中汞含量不同,但汞与其最近邻原子的键长是一致的,从而其配位情况也可能是相同的。通过比较所有样品的谱图可看出,头发样品与Hg(GS)_2的配位情况相似。

原子吸收分光光度法测定藏药二十五味珊瑚丸中5种重金属含量

目的:建立测定藏药二十五味珊瑚丸中5种重金属含量的方法,并考察西藏不同地区5个厂家生产的该药品中重金属含量情况。方法:以浓硝酸-高氯酸(4∶1,V/V)消解二十五味珊瑚丸样品,采用火焰原子吸收分光光度法测定其中铜(Cu)、铅(Pb)、镉(Cd)3种重金属元素的含量,氢化物发生原子吸收分光光度法测定其中砷(As)、汞(Hg)2种重金属元素的含量。结果:5种重金属元素含量检测在相应质量浓度范围内线性关系均良好(r均≥0.999 1);Cu、Pb、Cd元素的检测限分别为0.001 6、0.041 2、0.036 3mg/L,定量限分别为0.005 3、0.137 3、0.121 0 mg/L;As、Hg元素的检测限分别为0.325 7、0.692 3μg/L,定量限分别为1.085 7、2.307 7μg/L;精密度试验的RSD均≤5.54%(n=6);稳定性试验的RSD均≤3.79%;重复性试验的RSD均≤3.72%;平均加样回收率为91.34%~110.11%,RSD为0.66%~6.80%(n=6)。含量测定结果显示,5个厂家的样品中Cu含量皆未超标,但Cd、Hg含量均超标;其中还有4个厂家样品中Pb含量超标,2个厂家样品中As含量超标。结论:建立的含量测定方法的准确度、灵敏度较高,且稳定性、重复性较好,适用于二十五味珊瑚丸中5种重金属含量的测定;5个厂家生产样品均在一定程度上存在重金属超标问题。

流动注射氢化物发生原子吸收光谱法测定禽蛋中的硒

探讨了流动注射-氢化物发生-原子吸收光谱法测定硒时的最佳条件,建立了禽蛋中微量硒的流动注射-氢化物发生-原子吸收光谱分析方法。同时讨论了禽蛋中硒含量水平和富硒科学饲养提高禽蛋中硒含量在补硒食品中的发展前景。在优化的工作条件下,测定硒的检出限为0.25μg.L-1,线性范围0~60μg.L-1,相对标准偏差小于2.5%,加标回收率为95%~108%。此法克服了石墨炉法存在严重的基体干扰,需要加入适当基体改进剂以提高硒的灰化温度及传统间断氢化物发生-原子吸收光谱法分析速度慢、操作繁琐且手工进样带来的误差等缺点,操作简便、快速、灵敏度和自动化程度高。

氢化物发生辅助雾化火焰原子吸收法测定人发中的铅

使用氢化物发生辅助雾化的火焰原子吸收法 ,在K3Fe(CN) 6 HCl体系中 ,测定了头发中铅的含量。对酸度、氧化剂及浓度、NaBH4 的浓度及流速对Pb测定的影响分别进行了研究。与传统雾化火焰原子吸收法相比 ,本方法测铅的灵敏度提高了 13 4倍。方法的检出限为 2 8μg·L- 1 ,精密度 (RSD)为 1 4 %。用于测定人发中的Pb ,回收率达 96 %～ 99%。

涂锆石墨管石墨炉原子吸收法测定水样中的有机锡和无机锡

本文用涂锆石墨管石墨炉原子吸收光谱法直接进样测定了样品中总锡含量， 用氢化物发生－有机溶剂萃取石墨炉原子吸收光谱法测定了样品中的有机锡，并通过差减法求得无机锡含量。无机锡和有机锡的测定检测限分别为２７ｐｇ 和５８ ｐｇ，精密度为２．０４％ 和２．１３％ 。该方法可用于不同水样中有机和无机锡的测定，回收率在９０．５％ ～９８．５％ 之间。