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.

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 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.

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%.

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-非色散原子荧光光谱法测定粉饼化妆品中Pb,As和Hg含量

建立并优化了氢化物发生-非色散原子荧光光谱法(HG-NDAFS)测定10种粉饼化妆品中铅(Pb),砷(As)和汞(Hg)的含量。确定了较佳载气流速为400 mL/min,屏蔽气流速为800 mL/min。优化了负高压和灯电流,确定了原子化器高度为8 mm。优化还原剂体系时,选择了质量分数1.5%KBH4溶液。载流选择2.4 mol/L HCl。结果显示,Pb,As,Hg的加标回收率分别为83.44%~90.32%,83.22%~86.59%,81.43%~89.94%,加标回收率良好。10种粉饼中共检出2种粉饼中含有Pb(含量0.48和0.27 mg/kg),1种粉饼中含有As(含量0.62 mg/kg),1种粉饼中含有Hg(含量0.11 mg/kg)。10种粉饼中的Pb,As,Hg含量均未超标。本研究建立的HG-NDAFS测定粉饼化妆品中Pb,As和Hg含量的方法准确度高,可用于粉饼化妆品中Pb,As和Hg含量的检测。

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。

高盐食品基质中砷含量的测定

建立了一种基体匹配-动态反应池-电感耦合等离子体质谱法测定高盐食品基质中砷含量的方法,以解决高盐基体对砷测定的质谱干扰和基体干扰。研究电感耦合等离子体质谱法与氢化物发生原子荧光光谱法测定食品中总砷的技术要点,通过分析前处理消解方式、有机基质、氯含量和内标校正元素等对砷含量测定的影响,建立了高盐食品基质中砷含量的测定方法。实验结果表明,微波消解法并不太适用于氢化物发生原子荧光光谱法测定食品中总砷,有机基质和氯分别会对砷的质谱测定信号产生增敏效应和质谱干扰,74Ge比72Ge更适合作为电感耦合等离子体质谱法测定食品中总砷的内标元素。建立的检测方法定量限0.010 mg/kg,高盐基体中砷在0.010、0.025、0.20、0.50 mg/kg添加水平的回收率为91.50%~110.80%,相对标准偏差范围为0.76%~7.22%。本法和参照法对样品分析结果统计值均大于t0.90,10(1.81,双边),测定结果存在显著性差异,对实际样品测定结果表明动能歧视测定模式并不太适用于高盐食品基质样品中总砷的测定。该方法准确可靠,能用于高盐和高基体食品中砷含量的测定分析。

吡咯烷二硫代氨基甲酸铵螯合-浊点萃取-氢化物发生原子荧光光谱法测定饮用水中痕量汞

鉴于标准HJ 694—2014检测饮用水中汞的检出限较高,无法满足痕量汞的分析要求,提出以吡咯烷二硫代氨基甲酸铵(APDC)溶液为螯合剂,以非离子型表面活性剂Triton X-114溶液为萃取剂,通过浊点萃取的方式将饮用水中的痕量汞富集于表面活性剂相,采用氢化物发生原子荧光光谱法测定痕量汞的方法。水样经过滤、酸化后,分取50 mL水样,加入2.0 g·L^(−1)APDC溶液1.5 mL,5%(体积分数)Triton X-114溶液1.5 mL,调节混合溶液酸度至pH 6,于40℃平衡5 min,以2900 r·min^(−1)转速离心10 min,冰水浴中冷却5~10 min。弃去上层水相,在表面活性剂相中加入由磷酸三丁酯与乙醇按体积比1∶1混合配制的消泡剂300μL,用5%(体积分数)盐酸溶液稀释至5 mL,上机检测。结果显示:汞的质量浓度在2.0μg·L^(−1)以内和对应的荧光强度呈线性关系,检出限为0.002μg·L^(−1)。按标准加入法进行回收试验,回收率为86.8%~97.9%,测定值的相对标准偏差(n=6)不大于8.0%。方法检出限较标准HJ 694—2014低一个数量级,能够满足饮用水等清洁水样中痕量汞分析的检出限要求。

稀酸微波消解-氢化物发生原子荧光光谱法测定蔬菜中总汞

为践行食品检测工作“环保”的理念,以菠菜粉质控样品为研究对象,通过考察硝酸浓度、微波消解温度、赶酸条件以及其他检测条件对总汞测定的影响,建立稀酸微波消解-氢化物发生原子荧光光谱法测定蔬菜中总汞的方法,并对方法进行评价,对九江市售蔬菜中汞含量进行测定。结果表明,最佳消解液组成为5 mL硝酸(20%)+1.0 mL过氧化氢、微波消解最高温度为160℃、载流为HNO_(3)(5%)、负高压280 V、KBH_(4)浓度0.5%。新建立的方法检出限为0.000 1 mg/kg,汞在0~2.0μg/L线性关系良好,加标回收率为92.0%~106%,相对标准偏差RSD为2.5%~5.5%。方法操作简便,大幅度减少了前处理过程硝酸使用量,无需赶酸,精密度、重现性好,灵敏度、准确度高,推广应用前景广阔。

微波消解-氢化物原子荧光光谱法检测食品中的砷

采用微波消解法进行前处理,氢化物原子荧光光谱法检测食品中的砷元素。该方法与湿法消解相比,操作简单、耗时短且样品消解更彻底。通过优化仪器参数,本方法相关系数为0.99923;在检出限、定量限水平做样品加标,回收率范围分别为81.2%~92.6%,80.5%~99.8%;相对误差、变异系数范围分别为0.0964%~2.19%,0.348%~2.49%;在定量限、2倍定量限和3倍定量限水平加标的回收率在84.2%~99.6%。通过验证,各项均满足要求,该方法适用于食品中砷的检测。

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。

氢化物发生-原子荧光光谱法测定钨尾矿尾砂中的砷

钨尾矿尾砂中的砷会随着自然条件的变化或资源综合利用过程而发生迁移,污染存在扩大的风险,快速、准确测定钨尾矿尾砂中砷的含量,将为环境污染防治措施提供数据依据。采用盐酸、硝酸消解样品,加入硫酸消除钨对原子荧光光谱法测定砷的干扰,用抗坏血酸将砷(Ⅴ)预还原为砷(Ⅲ),在盐酸介质中,砷(Ⅲ)和硼氢化钾发生氢化反应生成砷化氢,经载气导入原子化器中测定砷量,并优化原子荧光光谱法测定条件,建立了氢化物发生原子荧光光谱法测定钨尾矿尾砂中砷的分析方法。砷的测定结果相对标准偏差(RSD,n=7)小于3%,加标回收率为93.9%~111%,同时采用钨含量与钨尾矿中钨含量相近的钨矿石成分分析标准物质做方法正确度验证,相对误差的绝对值<5%。实验结果表明,建立的方法测定钨尾矿尾砂中砷含量,具有操作简单、灵敏度高,干扰少、正确度高,测定速度快等优点。

水浴消解-原子荧光光度法测定土壤中的总砷和总汞

研究土壤中总砷和总汞的测定方法,样品采用王水消解,建立了水浴消解-原子荧光光度法测定土壤中总砷和总汞的方法。总砷的的检出限为0.70μg/kg,总汞的检出限为4.52μg/kg,总砷的的精密度是1.10%~1.73%,总汞的精密度1.20%~3.43%,总砷的回收率为91%~103%;总汞的回收率为103%~106%。该方法检出限、精密度、准确度、回收率均能满足土壤检测的要求,且前处理简单、快捷、高效,适用于土壤中总砷总汞的同时测定。

液相色谱-氢化物发生-原子荧光光谱法测定中药样品中的4种砷形态

目的 建立一种液相色谱-氢化物发生-原子荧光光谱测定中药样品中4种砷形态的方法。方法 以0.15 mol/L硝酸溶液为提取溶剂,提取处理后的中药样品,全自动石墨消解仪90℃热浸提,离心,取上清,0.45μm滤膜过滤后注入液相色谱仪,梯度洗脱,4种砷形态可在360 s中内完全分离,分离后的亚砷酸根[As(Ⅲ)]、砷酸根[As(Ⅴ)]、一甲基砷(MMA)、二甲基砷(DMA)4种砷形态进入氢化物发生-原子荧光光谱仪进行检测,根据保留时间定性,峰面积定量。结果 本方法在1.0~50.0μg/L范围内线性良好,相关系数(r)均>0.999,加标回收率为96.7%~101.9%,不同浓度水平的RSD均小于3%。所检测的7种中药材样品中,砷主要以As(Ⅲ)和As(Ⅴ)形态存在。结论 本方法前处理简便、检测速度快、检出限低、准确度和精密度较高,可用于中药材样品中4种砷形态的测定。

砷钼蓝分光光度法和氢化物发生—原子荧光光谱法测定煤中砷含量的比较分析

对砷钼蓝分光光度法和氢化物发生—原子荧光光谱法测定煤中砷的含量进行了比较分析,2种方法分别在砷含量0~50μg/g、0~40μg/g范围内符合朗伯—比耳定律,线性相关性良好;分别用2种方法对砷含量在0~40μg/g范围内的10个样品各进行2次重复测定,利用t检验和F检验法分别对2种方法的正确度(偏倚试验)和精密度进行了评估,得出氢化物发生—原子荧光光谱法与砷钼蓝分光光度法相比没有实质性偏倚的存在,2种方法的精密度均在规定范围内。

氢化物发生原子荧光光谱法测定食品中总砷的不确定度评定

本研究采用原子荧光法,以测定圆白菜中总砷含量的不确定度,分析影响不确定度的因素,包括称量、标准溶液配制、移液和仪器重复测量等主要因素引入的不确定度,并对不确定度各分量进行计算合成标准不确定度和扩展不确定度。结果显示,当氢化物发生原子荧光光谱法测定食品中总砷时,此不确定度可用于偏离幅度的计算。