Determination of Chromium (VI) in Airborne Particulate Matter by Electrothermal Atomic Absorption Spectrometry

Hexavalent chromium Cr(VI) is a well-established carcinogen associated with lung, nasal, and sinus cancer. Cr(VI) threshold limit values in workroom air have been recently lowered. Consequently, the currently available analytical methods are insufficiently sensitive or high cost. In this paper, a simple, cost-effective, sensitive, and reproducible method using solid-phase extraction with electrothermal atomic absorption spectrometry for determination of hexavalent chromium in airborne samples is reported. The method validation included selectivity, linearity, accuracy, and precision. Interferences from other ions likely to be present in airborne samples, including trivalent chromium, were tested and selectivity was demonstrated. The detection and quantification limits were, respectively, as low as 0.1 and 0.4?µg?L^?1. The linearity ranged from 0.5 to 50.0?µg?L^?1, with a regression coefficients exceeding 0.998. The extraction recovery exceeded 98%. The developed method was successfully compared with a reference spectrophotometric method. The performances achieved were similar to ion chromatography and high-performance liquid chromatography approaches. The novel method was tested on airborne samples collected from the workplace. The method’s performance suggests that it may be an alternative to high-cost techniques for monitoring occupational exposure to hexavalent chromium.     

电热鼓风干燥箱解脱–火焰原子吸收光谱法测定地质样品中金的含量

建立高海拔地区电热鼓风干燥箱解脱–火焰原子吸收光谱法测定地质样品中的金的方法。高海拔地区由于大气压低,水的沸点低,使得泡塑吸附金的解脱率不高。为了得到准确的分析结果,采用电热鼓风干燥箱代替水浴锅来解脱泡塑吸附金,优化后的解脱条件:解脱温度为105℃,解脱时间为30 min,在此条件下金的解脱率为91.19%。金的质量浓度在0.00~10.00μg/mL范围内与其吸光度呈良好的线性关系,相关系数r=0.999 6,方法检出限为0.012μg/mL。测定结果的相对标准偏差为2.15%(n=7),加标回收率为96.0%~102.5%。用该方法测定国家一级标准物质,测定结果与参考值相符。该方法准确、可靠,适用于高海拔地区地质样品中金的测定。     

浊点萃取-火焰原子吸收光谱法测定样品中的痕量钴

研究了基于表面活性剂Triton X-114和络合剂吡咯烷二硫代氨基甲酸铵（APDC）浊点萃取钴的样品前处理方法.优化了浊点萃取条件参数,包括pH值、Triton X-114用量、APDC浓度、平衡温度及时间等,建立了浊点萃取-火焰原子吸收光谱法测定痕量钴的方法.该法的检测限（3σ）为2.6μg/L,相对标准偏差RSD为6.2%（n=7,c=200μg/L）.该法成功地应用于海带、维生素B12注射液等样品中钴的测定.     

连续流动氢化物发生—原子吸收光谱法测定地质样品中痕量硒

经试验研究，选定了分析地质样品中痕量硒的测定体系，建立了切实可行的分析方法，该方法不需分离，直接测定，灵敏度高，干扰少，方法测定下限可达０．０２μｇ／ｇ，进行了部分样样分析，结果令人满意。     

Determination of Rhodium in Biological Materials by Electrothermal Atomic Absorption Spectrometry with a Tungsten Tube Atomizer

Abstract

Electrothermal atomic absorption spectrometry (ETAAS) of rhodium with a tungsten tube atomizer has been investigated under optimum conditions (atomization temperature; 2230 C, purge gas; Ar 480 ml min^?1 + H₂ 20 ml min^?1, and pyrolysis temperature; 590 C). The absolute characteristic mass (the mass of element giving 0.0044 abs.) of rhodium by the atomizer was 86.5 pg and the detection limit was 16.5 ng ml^?1 (3S/N). The interferences caused by large amounts of interferents were evaluated. Al, Ca, Cu, Fe, K, Mg, Na, Pb and Zn severely interfered in the AA signal of rhodium. Ammonium phosphate, ascorbic acid, palladium nitrate, copper nitrate, lanthanum nitrate, thiocyanate and thiourea, well known as matrix modifiers were tested to eliminate the severe interferences. However, by the addition of these compounds, the rhodium signal was not recovered. The standard addition method was adapted for the determination of rhodium in biological materials. The recovery of spiked-rhodium in biological materials was in the range of 97.4 to 107%.     

Determination of Ultratrace Amounts of Copper（ Ⅱ ） in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

IntroductionIn environment, copper is usually found in traceor ultratrace levels, and its detection requires sensitiveinstrumental measuring techniques such as electrother-mal atomic absorption spectrometry(ETAAS) and ICP-AES or ICP-MS. Frequently, a prec…     

甲基异丁基甲酮萃取石墨炉原子吸收光谱法测定地质样品中的痕量银

建立了石墨炉原子吸收光谱法测定痕量银的方法。研究了仪器工作参数、分离条件及共存离子的干扰,确定了最佳测定条件。结果表明:地质样品经焙烧,用氢氟酸–盐酸–硝酸–高氯酸溶矿,在5%的盐酸介质中加入0.5m L 200 g/L的抗坏血酸溶液及0.25 m L 300 g/L的碘化钾溶液,并以2.0 m L 50 g/L的EDTA溶液掩蔽Cu2+,Pb2+,用2.0 m L甲基异丁基甲酮萃取分离银,在灰化温度500℃、原子化温度2 200℃条件下进行有机相测定。方法检出限为0.084μg/L,测定结果的相对标准偏差为1.89~3.91%(n=6),对国家一级标准物质测定,结果与标准值相符合。     

Determination of Ultratrace Amounts of Copper(Ⅱ) in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

A novel approach was developed for the determination of ultratrace amounts of copper in water samples by using electrothermal atomic absorption spectrometry (ETAAS) after cloud point extraction (CPE). 1-( 2-Pyridylazo)-2-naphthol was used as the chelating reagent and Triton X-114 as the micellar-forming surfactant. CPE was conducted in a pH 8.0 medium at 40 ℃ for 10 min. After the separation of the phases by centrifugation, the surfactant-rich phase was diluted with 1 mL of a methanol solution of 0. 1 mol/L HNO3. Then 20 μL of the diluted surfactant-rich phase was injected into the graphite furnace for atomization in the absence of any matrix modifier. Various experimental conditions that affect the extraction and atomization processes were optimized. A detection limit of 5 ng/L was obtained after preconcentration. The linear dynamic range of the copper mass concentration was found to be 0-2.0ng/mL, and the relative standard deviation was found to be less than 3.1% for a sample containing 1.0 ng/mL Cu(Ⅱ). This developed method was successfully applied to the determination of ultratrace amounts of Cu in drinking water, tap water, and seawater samples.     

Determination of Tributyltin in Oysters by Electrothermal Atomic Absorption Spectrometry

Abstract

Graphite-furnace atomic absorption spectrometry for tributyltin in oysters is described. Tributyltin is extracted by n-hexane after digestion with hydrochloric acid. The 3[sgrave] detection limit for tributyltin is better than 0.01 mg Sn/kg. Typical absorbance values are about 0.10 for tributyltin contents as low as 0.03 mg Sn/kg. Tributyltin contents of 29 oyster samples are given.     

Determination of Hg(II) and Methylmercury by Electrothermal Atomic Absorption Spectrometry after Dispersive Solid-Phase Microextraction with a Graphene Oxide Magnetic Material

The toxicity of all species of mercury makes it necessary to implement analytical procedures capable of quantifying the different forms this element presents in the environment, even at very low concentrations. In addition, due to the assorted environmental and health consequences caused by each mercury species, it is desirable that the procedures are able to distinguish these forms. In nature, mercury is mainly found as Hg⁰, Hg²⁺ and methylmercury (MeHg), with the latter being rapidly assimilated by living organisms in the aquatic environment and biomagnified through the food chain. In this work, a dispersive solid-phase microextraction of Hg²⁺ and MeHg is proposed using as the adsorbent a magnetic hybrid material formed by graphene oxide and ferrite (Fe₃O₄@GO), along with a subsequent determination by electrothermal atomic absorption spectrometry (ETAAS). On the one hand, when dithizone at a pH = 5 is used as an auxiliary agent, both Hg(II) and MeHg are retained on the adsorbent. Next, for the determination of both species, the solid collected by the means of a magnet is suspended in a mixture of 50 µL of HNO₃ (8% v/v) and 50 µL of H₂O₂ at 30% v/v by heating for 10 min in an ultrasound thermostatic bath at 80 °C. On the other hand, when the sample is set at a pH = 9, Hg(II) and MeHg are also retained, but if the solid collected is washed with N-acetyl-L-cysteine only, then the Hg(II) remains on the adsorbent, and can be determined as indicated above. The proposed procedure exhibits an enrichment factor of 49 and the determination presents a linear range between 0.1 and 10 µg L⁻¹ of mercury. The procedure has been applied to the determination of mercury in water samples from different sources.     

Determination of Cobalt with a Tungsten Tube Atomizer by Electrothermal Atomic Absorption Spectrometry and its use for the Analysis of Biological Materials

 The determination of cobalt by electrothermal atomic absorption spectrometry with a tungsten tube atomizer has been investigated. The absolute characteristic mass (the mass of element giving 0.0044 abs.) of cobalt by the atomizer was 5.8 pg and the detection limit was 0.65 ng/ml (3S/N). The interferences caused by large amounts of interferents like Al, Ca, Cu, Fe, K, Mg, Na, Pb and Zn were evaluated and most of these elements were found to interfere with the cobalt signal. Ammonium thiocyanate as a chemical modifier was found to be efficient to eliminate the severest interferences. The accuracies of the recommended method were found to be almost satisfactory for the determination of cobalt in biological materials, as shown by a comparison with the reported values of NIST materials at the 0.02–0.4 μg/g level. Received August 24, 1998. Revision February 9, 1999.     

电热蒸发进样微波诱导等离子体原子吸收光谱法测定银和镉的研究

研究了以常压低功率氩微波诱导等离子体（ＭＩＰ）为原子化器的原子吸收光谱法（ＡＡＳ）测定银和镉。采用电热蒸发（ＥＴＶ）,浓Ｈ２ＳＯ４吸收去溶的进样方法。考察了微波前向功率,载气流量,去溶电压,去溶时间,蒸发电压,酸度对银,镉测定的影响。方法已用于试样分析。     

Design and Critical Evaluation of Improved Electrothermal Vaporization Flame Atomic Absorption/Emission Spectrometry for Direct Determination of Trace Metals in Microliter Samples

Improved tantalum-filament electrothermal vaporization flame atomic absorption spectrometry (ETV-FAAS) was developed and used for the direct determination of trace metals in microliter samples. Studies have been made for optimizing the experimental parameters that affect the performance of sample introduction to the flame. Linear calibration graphs are shown for the elements Mn (10–200 ng), Pb (5–200 ng), Cu (5–100 ng), Cd (5–50 ng), Li (1–20 ng), Na (10–80 ng), and K (10–80 ng), using only 10 μl of standard solutions. The detection limits of the elements by ETV-FAAS were much lower than those of conventional FAAS. Absolute detection limits for all elements studied were less than 0.1 ng. The relative standard deviation values for the elements were <10%. The developed method was also applied to the determination of lead concentration in blood samples.     

Electrothermal Atomic Absorption Spectrometric Determination of Cobalt,Copper and Nickel in Fresh Water After Their Preconcentration by Precipitate Flotation

Abstract

A method is developed for simultaneous separation and determination of μg/L levels of Co(II), Cu(II) and Ni(II) in fresh water by precipitate flotation. The optimal conditions of the experimental procedure with hydrated iron(III) oxide and iron(III) tetramethylenedithiocarbamate as collectors were investigated. The pH interval of the working medium, within which Co(II), Cu(II) and Ni(II) can be successfully separated, was determined from the aspect of collectors and surfactant stability. The amounts of the elements investigated were determined by electrothermal atomic absorption spectrometry. The detection limit of the method is 0.15 μg/L for cobalt, 0.03 μg/L for copper and 0.79 μg/L for nickel.     

顺序注射-样品预处理模块系统-电热原子吸收法测定海水中痕量铜

将样品预处理模块与自动化顺序注射系统相结合,建立了未经稀释的海水中痕量铜的分离富集方法。铜-PDC螯合物在样品预处理模块中被吸附在聚四氟乙烯微珠填充柱上,用少量甲醇洗脱后,将洗脱液引入电热原子吸收中测定。进样体积为1.0mL时,富集倍率为20,检出限为0.015μg/L,采样频率为26次/h,线性范围为0.05~1.00μg/L,相对标准偏差(RSD)为1.8%(0.50μg/L)。利用本方法分离富集并测定了标准海水样品NASS-5及近海水样中的铜含量,并进行了加标回收实验。     

Ultra‐Trace Silver Determination in Biological and Water Samples by Electrothermal Atomic Absorption Spectrometry after Electrodeposition on a Graphite Probe

A rapid and simple procedure was developed for selective and sensitive determination of ultra‐trace silver in biological and environmental samples using the electrodeposition on a graphite probe modified with palladium followed by electrothermal atomic absorption spectrometry. Several experimental parameters for the electrodeposition, such as deposition potential, electrolyte concentration, pH of solution and deposition time were optimized. The calibration graph after preconcentration was linear in the range of 10‐250 ngL^?1 with correlation coefficient of 0.9989 under the optimum conditions for procedure. The limits of detection (LOD) and quantification (LOQ) base on (3σ) and (10σ) were 2.8 ngL^?1 and 9.4 ngL^?1 respectively. Related standard deviation (RSD) for eight replicate measurements of 100 ngL^?1 silver was 4.3%. Samples were digested completely in a closed microwave digestion system using only perchloric acid, and interference owing to various cations was also investigated. The proposed procedure was successfully applied to determine silver in blood, urine and some environmental samples with satisfactory analytical results.     

Activated Carbon Modified with Sodium Dodecyl Sulfonate as a Solid Phase Sorbent for the Separation and Preconcentration of Trace Cadmium in Water Samples with Detection by Electrothermal Atomic Absorption Spectrometry

A novel absorbent was prepared by sodium dodecyl sulfonate (SDS)-modified activated carbon (SDS-AC) and was employed as the microcolumn packing material for separation/preconcentration of trace Cd(II). The method based on Cd(II) was quantitatively retained by SDS-AC sorbent, which entailed cation exchange nature and negative charged surface, facilitating favorable retention of positively charged ions. The retained Cd(II) was effectively recovered with elution by 1 mol · L^?1 HNO₃, and the eluent was quantified by electrothermal atomic absorption spectrometry (ET-AAS). Under the optimized conditions, the limit of detection (LOD) for Cd(II) was 3 ng · L^?1 with the consumption of 20.0 mL sample solution. The relative standard deviation (RSD) for ten replicate measurements of 50 ng · L^?1 Cd(II) was 2.9%. The developed technique was demonstrated for the determination of trace Cd(II) in water samples and the recoveries for spiked samples were found to be in the range of 94.9–107.2%. For validation, two certified reference materials of water samples (GBW08607 and GBW08608) were analyzed, and the results obtained were in good agreement with the certified values.     

Flame Atomic Absorption Spectrometric Determination of Trace Cadmium in Alloys and Biological Samples After Solid–Liquid Extraction and Preconcentration with Use of Nitroso-S

 Cadmium is quantitatively retained by 2-nitroso-1-naphthol-4-sulfonic acid (nitroso-S) and tetradecyldimethylbenzylammonium chloride (TDBA) on microcrystalline naphthalene in the pH range 5.7–10.5 from a large volumes of aqueous solutions of various samples. After filtration, the solid mass consisting of cadmium complex and naphthalene is dissolved with 5 mL of dimethylformamide and the metal was determined by flame atomic absorption spectrometric. Cadmium complex can alternatively be quantitatively adsorbed on tetradecyldimethylbenzylammonium-naphthalene adsorbent packed in a column and determined similarly. About 25 ng of cadmium can be concentrated in a column from 500 mL of aqueous sample, where its concentration is as low as 0.05 ng/mL. Eight replicate determinations of 0.1 μg/mL of cadmium in final DMF solution gave a mean absorbance of 0.060 with a relative standard deviation of 1.8%. The sensitivity for 1% absorption was 7.3 ng/mL. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of cadmium in various alloys and biological samples. Correspondence: Department of Chemistry, Shahid Bahonar University, Kerman, Iran. e-mail: ma_taher@yahoo.com Received March 30, 2001; accepted January 18, 2002     

微乳相萃取分离富集-原子吸收光谱法分析铬形态

建立了一种微乳相萃取分离-石英双缝管原子捕集火焰原子吸收光谱法(STAT-FAAS)分析环境水样中铬形态的新方法。该方法中,Cr(Ⅲ)与8-羟基喹啉反应形成的疏水性配合物,经萃取进入微乳相,Cr(Ⅵ)留在水溶液中,从而实现Cr(Ⅲ)与Cr(Ⅵ)的相互分离。Cr(Ⅵ)含量的测定通过过氧化氢溶液将Cr(Ⅵ)还原为Cr(Ⅲ),按同样方法分析。实验对微乳相萃取的主要影响因素进行了优化。结果表明,经优化后实验条件为:平衡温度80℃,平衡时间10min,溶液酸度pH=9.0,NH3-NH4Cl缓冲溶液用量2.0mL,8-HQ用量0.05mmol;TritonX-100微乳液组成:m(TritonX-100):m(正戊醇):m(正己烷):m(水)=3.0:15:1.5:4.0。在此条件下,萃取的富集倍数达到25倍(50mL起初样品溶液/2mL最终测定液),线性范围为2.5～500μg/L,检出限为0.62μg/L,相对标准偏差(RSD)为3.8%(n=10,c=10μg/L)。本方法已成功地应用于电镀废水中铬形态分析。     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的镉

建立了浊点萃取分离富集石墨炉原子吸收光谱法测定环境样品中痕量镉的方法.浊点萃取选择8-羟基喹啉为螯合剂,Triton X-100为表面活性剂.在pH 8～9、0.01%8-羟基喹啉和0.2%-Triton X-100、80 ℃水浴20 min的优化条件下,所建立方法的检出限为2.5 ng/L; 加标回收率为94.6%～106.2%; 对样品溶液进行富集的富集因子为17.利用该方法分别测定了2个实际水样和2个国家标准参考物质中的总镉含量,结果令人满意.