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 total selenium in geological samples by HG-AFS after concentration with thiol cotton fiber

Standard reference material and different geological samples were dissolved by system A (the mixture of nitric and perchloric acids) and system B (mixture of nitric, perchloric and hydrofluoric acids), and total Se in all samples was measured by hydride-generation atomic fluorescence spectrometry (HG-AFS) after concentration with thiol cotton fiber (TCF). The analytical results obtained by the two digestion method are in good agreement (within the limit of errors) for most of the samples, particularly for those having recommended values. The Se concentrations determined by the two methods are of no difference, and the correlation coefficient is 0.9986; the relative standard deviation (RSD) for the determination of 0.04 μg/g Se is 10.2%. The recovery rates of systems A and B by the stan- dard-addition method were 96%–106% and 99%–104%, respectively.

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 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%.

Determination of Hg in soil by ultrasonic slurry sampling hydride generation atomic fluorescence spectrometry

Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry （USS-HG-AFS） was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was suspended in agar solution by an ultrasound water bath before the HG-AFS determination. The results for the reference material of soil （serial number GBW-07411） agreed satisfactorily with the certified values. Results obtained by the developed procedure compared well with those after traditional acid digestion of samples. The detection limit are 6.7ngL-1 for Hg respectively, with average relative standard deviation values of 6.4% for analysis of a series of soil samples of different origin. The recoveries of the anatytes varied in the range from 95 to 107%. This observation has stimulated interest in fast, accurate and sensitive analytical methods for determination of metals in soil.

Determination of Cadmium in TSP, PM10 in urban areas by hydride generation atomic fluorescence spectrometry

In this paper, two different diameter particles （TSP, PM10） were collected by TH-16A four-channels classification air sampler. The samples were treated by HNO3. Analysis of cadmium was carried out by hydride generation atomic fluorescence spectrometry （HG-AFS） method, and distribution proportions of elements in four phases were calculated. This method was based on the reaction of cadmium with 1.5% （m/v） KBH4 solution and 0.5% KOH（m/v） solution to form the hydride gas in medium of 2% （v/v） HCl. The detection limit for cadmium as low as 0.008μg/L was obtained. The lineally correlation coefficient was 0.99992. The relative standard deviation （n=5, C=1.00μg/L） was 3.26%. The proposed method was applied for the determination of cadmium in atmosphere aerosol samples and the recoveries in the range of 95-102.2% were obtained. This method was simple, rapid, less matrix interference and high sensitivity.

高效液相色谱-氢化物发生-原子荧光光谱法测定富硒大豆中硒代氨基酸的含量

取0.1 g脱脂后富硒大豆样品于离心管中,用5 mL pH 7.5的130 mmol·L^(-1)三(羟甲基)氨基甲烷-盐酸缓冲液超声振荡30 min,用15 mg链霉蛋白酶于37℃振荡酶解5 h,离心后取上清液,过0.22μm尼龙有机滤膜。滤液中的硒代半胱氨酸(SeCys)、硒代蛋氨酸(SeMet)、甲基硒代半胱氨酸(MeSeCys)在Agela MP-C_(18)色谱柱上分离,以含2%(体积分数)甲醇和0.5 mmol·L^(-1)四丁基溴化铵的40 mmol·L^(-1)磷酸氢二铵溶液(pH 7.0)进行等度洗脱,并采用氢化物发生-原子荧光光谱法测定3种硒代氨基酸的含量。结果表明,3种硒代氨基酸在7 min内可以实现基线分离,标准曲线的线性范围均为5~100μg·L^(-1),检出限依次为0.086,0.075,0.047 mg·kg^(-1)。按照标准加入法进行回收试验,回收率为85.5%~103%,测定值的相对标准偏差(n=7)不大于3.0%。方法用于分析富硒大豆中的硒代氨基酸,大豆中硒赋存形态多为SeMet,含量占总硒量的85.5%~94.5%。

氢化物发生-原子荧光光谱法(HG-AFS)测达里诺尔湖流域底泥样硒

氢化物发生-原子荧光光谱法(HG-AFS)是测定硒(Selenium,Se)的理想方法,能精确测定水样和含水地球化学样品(底泥)中Se的含量。由于达里湖底泥中Se含量相对较低,有机质的还原状态较高,在测量Se含量时往往因为过于复杂且低于仪器检出限而不能被检测到有效值。该文应用HG-AFS测定达里诺尔湖底泥中Se的含量,使用微波消解石墨赶酸作为前处理方法,并使用HG-AFS进行Se含量的测试,采用此法测定底泥中Se元素具有快速、准确、重现性好,被确定为一种快速可靠的对底泥样品Se含量进行测定的方法。

微波消解-氢化物原子荧光光谱法测定胡萝卜硒含量

硒是人体内各种含硒酶及含硒蛋白的合成过程中必不可少的一种微量元素,能提高身体的免疫功能。硒对人体有一定的防癌作用,硒不但对肿瘤有抑制作用而且还能影响致癌物质的新陈代谢,素有“防癌之王”之称。采用人工栽培方式生产的富硒胡萝卜是一种较为理想的富硒型蔬菜。该文以胡萝卜为研究对象,利用微波消解-氢化物原子荧光光谱法测定胡萝卜中总硒的含量,探讨不同微波消解溶剂和消解条件对含硒胡萝卜消解效果的影响,并优化氢化物原子荧光光谱法测定条件。结果表明,最佳消解体系为HNO_(3)-H_(2)O_(2)体系(5 mL∶2 mL);最佳微波消解条件为,第一工步为2 min、0.2 MPa;第二工步为6 min、0.5 MPa和6 min、0.7 MPa;第三工步为5 min、1 MPa;在最优条件下,测硒的线性范围为0~50μg/L。对样品空白荧光值进行10次测定,RSD=2.24%,最低检出限为0.90μg/kg。土壤中施硒能够显著提高胡萝卜中总硒的含量,较空白对照组提高6.50%(地上)和10.30%(地下),可食用(地下)部位的最高硒含量为445.90μg/kg。

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.

高压密闭消解-氢化物发生原子荧光光谱法测定农作物中硒的含量

提出了高压密闭消解-氢化物发生原子荧光光谱法测定农作物中硒含量的方法。粮食类样品(干样)去除杂物后,用水洗净,于60℃烘干;蔬菜类样品(鲜样)用水洗净,晾干,取可食用部分,制成匀浆。取上述样品0.5000 g置于高压密闭聚四氟乙烯(PTFE)内罐中,加入8 mL硝酸和2 mL 30%(质量分数)过氧化氢溶液,混匀过夜,于150℃密封消解4 h。冷却至室温后,于150℃赶酸至约1 mL,加入50%(体积分数)盐酸溶液5 mL,于150℃继续保持加热至溶液无色清亮并伴有白烟冒出。冷却后转移至10 mL容量瓶中,加入100 g·L^(-1)铁氰化钾溶液2.5 mL,用水定容。所得溶液在硒高性能空心阴极灯电流为80 mA,载气流量为300 mL·min^(-1),屏蔽气流量为700 mL·min^(-1)的条件下,采用氢化物发生原子荧光光谱法测定其中硒的含量。结果表明,硒的质量浓度在100μg·L^(-1)以内与对应的荧光强度呈线性关系,检出限(3s)为0.001 mg·kg^(-1)。方法用于国家标准物质分析,测定值的相对标准偏差(n=12)为2.3%~7.1%,相对误差为-6.7%~9.7%。方法还用于实际样品分析,所得测定结果与国家标准GB 5009.93-2017基本一致。

六价硒在氢化物原子荧光法测定时的转化条件研究

以我国具有完全知识产权的原子荧光仪为检测工具,运用氢化物原子荧光法对水中六价硒转化为四价硒的条件进行探索,研究了六价硒转化与放置反应时间、反应温度、盐酸加入浓度的关系,以期为水质检测工作提供一些有价值的参考。

湿法消解-氢化物原子荧光光谱法测定小米中硒含量

目的:建立湿法消解-氢化物原子荧光光谱法测定小米中硒含量的分析方法。方法:小米试样经混合酸消解后,加入(1+1)盐酸溶液还原,使用原子荧光光谱仪在线检测。结果:硒在0~20.0μg·L^(-1)线性良好,相关系数为0.9997,方法检出限为0.0002 mg·kg^(-1),加标回收率为95.0%~104.8%,相对标准偏差为3.20%~3.92%。结论:本方法灵敏度高,准确高,检测周期短,可操作性强,适用于大批量小米样品中硒含量的分析检测。

微波消解-氢化物原子荧光法测定高含量硒的工艺探究

本文采用微波消解-氢化物原子荧光法测定高含量硒。用硒含量作为评价指标进行单因素和正交试验,确定最优处理条件。结果表明,当称样量为0.10 g、消解温度为200℃、消解液配比为11 mL硝酸+1 mL双氧水,盐酸添加量为6 mL和定容体积为500 mL时,测定的硒含量为122.78 mg·kg^(-1),且加标回收率高,试验稳定性好。

氢化物发生-原子荧光光谱法测定中草药中的硒

本文建立了氢化物发生-原子荧光光谱法测定中草药中的微量硒的分析方法。研究了仪器的工作条件、试剂对硒原子荧光强度的影响及硒(Ⅵ)的还原条件,探讨了共存离子对硒测定的干扰和消除方法,方法的检出限为0.21μg·L^(-1)。利用本方法成功地测定了10种中草药中的微量硒,回收率为95％～105％。方法简便、快速、灵敏、准确。

氢化物发生-原子荧光光谱法测定植物样品中的硒

建立了氢化物发生-原子荧光光谱法测定植物样品中硒的分析方法。研究了试剂及预还原方式对硒原子荧光强度的影响,探讨了共存离子对硒测定的影响和消除方法。在最佳消解条件和测定条件下,硒的线性回归方程为I=139.98c+27.71,线性范围为0～10ng.mL-1,相关系数为1.000 0,检出限为1.45ng.g-1。测定标准物质中硒的回收率为98.9%～101%,其平均值为100%。对灌木枝叶样品中的硒进行分析,其相对标准偏差为0.73%(n=9)。以国家标准物质(GSV-1)为监控样品,测定值与标准值吻合。该方法具有成本低、操作简单和高效分析的优点,并成功用于植物样品中硒的测定。

液相色谱-氢化物发生原子荧光光谱法测定富硒酵母中硒的形态

建立了富硒酵母中硒酸Se（Ⅵ）、亚硒酸Se（Ⅵ）、硒代蛋氨酸（SeMet）和硒甲基硒代半胱氨酸（SeMeCys）4种硒形态的高效液相色谱-氢化物发生原子荧光光谱（HPLC-HG-AFS）分析方法。样品采用蛋白酶和胰蛋白酶酶解提取,20 mmol/L（NH4）2HPO4为流动相,经PRP-X100阴离子交换色谱柱分离后HG-AFS测定。结果显示,4种硒形态标准曲线的线性关系良好（R^2≥0.9995）,方法检出限为0.5~5.0μg/kg,平均回收率为82.5%~101.2%,日内相对标准偏差≤8.6%,日间相对标准偏差≤14.5%。本方法前处理简单、灵敏度高、设备便宜、运行费用低廉,适用于富硒饲料产品中硒的形态分析。

蔬菜中硒总量及形态的氢化物发生-原子荧光光谱测定方法

采用氢化物发生原子荧光光谱法（HG-AFS）测定了几种蔬菜中的总硒含量,并测定了其中无机硒和有机硒的相对含量。实验优化了仪器测量参数,考察了载流盐酸和硼氢化钾浓度、样品介质盐酸浓度和残留硝酸浓度及干扰元素对测定的影响。结果表明：几种蔬菜中硒的含量都较低,而草菇的硒含量达到0.151μg·g^-1。此外,蔬菜中硒主要以有机硒的形态存在。方法的检出限为0.35 ng·g^-1,加标回收率为97.6%-101%。实验方法操作简便、灵敏度高,结果令人满意。

氢化物发生-原子荧光法测定鸭蛋中无机硒和有机硒

建立鸭蛋中有机硒和无机硒的测定方法,采用pH8.6的三羟甲基氨基甲烷-盐酸(Tris-HCl)缓冲溶液提取,硫酸铵沉淀后获得无机硒溶液,采用原子荧光法测定其中的总硒和无机硒,采用差减法计算有机硒的含量。结果表明,在优化的条件下,方法无机硒检出限0.003mg/kg,线性范围2.0～50μg/L,相对标准偏差3.21%,方法的加标回收率为82.8%～91.0%。该方法简便、灵敏,可为鸭蛋中有机硒和无机硒的测定提供了一种完善检测方法。