The use of dithizone extraction and atomic absorption spectrometry for the determination of cadmium,zinc, copper,nickel and cobalt in rocks and sediments

A method is presented for the determination of cadmium, zinc, copper, nickel and cobalt in sediments. The sediments are digested with hydrofluoric, sulphuric and perchloric acids. The metals are extracted into dithizone. Cadmium and zinc are back-extracted into dilute hydrochloric acid, but the other metals are determined in a solution prepared after the destruction of the organic extract. The method has been applied to USGS rock reference samples and to estuarine sediments.     

Chemical analysis of manganese nodules: Part IV. Determination of Nickel after Anion-exchange Separation

A method is described for the a.a.s. determination of nickel in manganese nodules after its separation from interfering metals. After dissolution of the sample in a mixture of perchloric and hydrofluoric acids, manganese, iron, cobalt, copper and other elements are adsorbed on the strongly basic anion exchange resin Dowex 1 (chloride form) from 95% ethanol-5% 12 M hydrochloric acid. The nickel passes into the effluent in which it is determined by a.a.s. with an air-acetylene flame. The method was used successfully for the determination of nickel in numerous samples of nodules from the Pacific Ocean.     

A simple decomposition and chelating resin separation for the determination of heavy metals in silicates by atomic absorption spectrometry

A simple method for the determination of copper, nickel, zinc, and cadmium in silicate rock samples is reported. Silicates are decomposed with hydrofluoric acid and aqua regia in a sealed Teflon vessel. After centrifugation and addition of malonic acid, the supernatant liquid is passed through a small column of Chelex 100. The metals are eluted with 2 M nitric acid, and determined by atomic absorption spectrometry. The method is rapid, simple, and free from contamination. The results obtained for 14 standard reference rock samples (USGS, GSJ, and CSRM) agree with literature data; the recovery, reproducibility, and accuracy of the proposed method are satisfactory.     

The simultaneous determination of copper and nickel by solvent extraction and gas-liquid chromatography with bis (acetylpivalylmethane) ethylenediimine as reagent

The copper(II), nickel(II) and palladium(II) chelates of the bridged β-ketoamine, bis(acetylpivalylmethane) ethylenediimine, are described. The copper and nickel complexes are readily extracted by cyclohexane at pH 8.0 from aqueous solution. The gas chromatographic separation of the copper and palladium, the nickel and palladium, and the copper and nickel chelates is reported on a silicone gum rubber phase (E-350) supported on Universal B at 285°C. Optimal conditions for the complete separation of copper and nickel are reported; the solvent extraction—gas chromatographic procedures are applied to the determination of the individual metal ions (limit of detection, 1 ng) and to the simultaneous determination of copper and nickel in solution and in alloy samples. A rapid method for the determination of copper in domestic water samples is also described.     

微波消解ICP-AES法测定高速工具钢中锰、磷、镍、铜、铬、钒

高速工具钢为高碳高合金工具钢,常温下样品酸溶分解较为困难。本文利用微波消解提高溶样的温度和压力,在王水、氢氟酸和硫酸介质中使样品充分消解,再用饱和硼酸溶液络合过量的氢氟酸,基体匹配消除铁基体的影响,ICP-AES法同时测定锰、磷、镍、铜、铬、钒的含量。测定高速工具钢标样,测定值与标样值相吻合,本方法的精密度在0.55%～4.06%。加标回收率在95.6%～114.8%,满足测定要求。     

Determination of metals in urine by direct injection of sample,high-performanc liquid chromatography and electrochemical or spectrophotometric detection

A method for the rapid and simultaneous determination of copper, nickel and lead in urine is described. Direct injections of freshly acidified and filtered (0.45-μm) urine samples were made onto a reverse-phase separator column with a guard column for sample clean-up. By complexing the metals with a dithiocarbamate ligand included in the mobile phase, the metal complexes could be detected electrochemically (copper and nickel) or spectrophotometrically (copper, nickel and lead). The procedure is shown to provide a convenient method for the determination of copper and nickel at normal to occupationally exposed levels of urinary output (electrochemical detection) after direct injection of samples. Spectrophotometric detection methods were insufficiently sensitive for direct determinations of copper and nickel at some of the lower levels found in urine. The spectrophotometric detection of lead is subject to interference by u.v.-absorbing constituents present in urine and is restricted to detection of lead in persons over-exposed to lead, unless additional clean-up procedures are applied.     

Reduction des interferences sur la determination des metaux lourds dans les sediments de cours d'eau et les boues de stations d'epuration par spectrometrie d'absorption atomique en four graphite

(Reduction of interferences in the determination of trace heavy metals in river sediments and sewage sludges by electrothermal atomic absorption spectrometry.)The interferences of synthetic matrices of river sediments and sewage sludges in the determination of lead, copper, cadmium, chromium and nickel by electrothermal atomic absorption spectrometry were studied; Pb, Cd and Ni were the most sensitive to interferences. The effects of hydrochloric, nitric, perchloric and hydrofluoric acids were tested; perchloric acid was found to interfere most during the determinations. Hydrofluoric acid must be eliminated by evaporation. Techniques for reducing chemical interferences were evaluated. The best method was found to be matrix modification with ammonium dihydrogenphosphate and ascorbic acid for the determination of lead and nickel, and rapid heating (Max Power) for the determination of cadmium. Determinants of copper and chromium were less prone to interference.     

ICP-AES法测定红土镍矿中镍、钙、钛、锰、铜、钴、铬、锌与磷的含量

建立了ICP-AES法测定红土镍矿中Ni;Ca;Ti;Mn;Cu;Co;Cr;Zn和P含量的方法。样品用HCl、HNO3溶解,加入HF和HClO4,加热至HClO4烟冒尽,用HCl溶解盐类,过滤,采用ICP-AES法同时测定滤液中Ni、Ca、Mn、Cu、Co、Zn、P;残渣经灼烧、挥硅、K2S2O7熔融、HCl浸取,所得溶液与滤液合并,测定溶液中Cr和Ti含量。方法检出限:P为0.022μg/mL,其它元素在0.0032～0.0085μg/mL之间,方法的精密度(n=7)在1.4%～2.9%之间。分析结果与分光光度法、XRF法和AAS法分析结果的相对误差:Ni、Cu、Co、Cr小于5%,Ti和Mn小于10%,Zn小于15%,Ca和P小于19%。     

Determination of tin and titanium in soils, sediments and sludges using electrothermal atomic absorption spectrometry with slurry sample introduction

Fast-heating programmes for determining titanium and tin in soils, sediments and sludges using electrothermal atomic absorption spectrometry (ETAAS) with slurry sampling are developed. For titanium determination, suspensions are prepared by weighing 5-40 mg of sample and adding 25 ml of a solution containing 50% (v/v) concentrated hydrofluoric acid. For tin determination, suspensions are prepared by weighing up to 300 mg of sample and then adding 1 ml of a solution containing 25% (v/v) concentrated hydrofluoric acid. Palladium (30 μg) and ammonium dihydrogen phosphate (7% w/v) are used as matrix modifiers for titanium and tin, respectively. Prior mild heating in a microwave oven is recommended for titanium determination. Calibration is carried out using aqueous standards. The tin and titanium contents of a number of samples obtained by using the slurry approach agree with those obtained by means of a procedure based on the total dissolution of the samples using microwave oven digestion. The reliability of the procedures is also confirmed by analysing several certified reference materials.     

Semi-automatic method for determination of total tin in rocks

Automatic equipment is used to generate tin hydride from sample solutions prepared by fusion of powdered rock with lithium metaborate followed by digestion with hydrofluoric and sulfuric acids. The evolved hydride is swept by argon into an electrically heated quartz tube atomizer. The atomic absorption of tin is measured at 224.6 nm. Oxalic acid and 1,10-phenanthroline are used to minimize interferences from iron, copper, and nickel. The detection limit of tin in the rock samples is 0.5 ppm. Results for reference rock samples agree closely with published values. A direct acid digestion procedure produces similar results for tin in many samples.     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜砷滤饼中的Pb、Fe、Bi三种元素

采用硝酸、盐酸、氢氟酸、高氯酸分解样品,氢溴酸-盐酸挥发消除砷基体,优化仪器测定参数,选取最佳工作条件,建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定铜砷滤饼中Pb、Fe、Bi元素的分析方法。其测定范围为：ω(Pb):0.12%~2.09%;ω(Fe):0.081%~2.10%;ω(Bi):1.20%~6.14%。各元素检出限为Pb:0.010μg/mL;Bi:0.006μg/mL;Fe:0.003μg/mL。加标回收率为95.5%~101.7%。该方法简便,准确,可靠,适用于铜砷滤饼中Pb、Fe、Bi元素的同时测定。     

Spectrophotometric determination of calcium in zirconium powder by use of murexide

An accurate spectrophotometric method is proposed for the determination of calcium in zirconium powder by use of murexide. A 0.4-g sample is dissolved in hydrofluoric and sulphuric acids, the solution evaporated to fumes of sulphuric acid, and a mercury cathode electrolysis made if more than 0.05% copper or nickel is present. Ammoniacal precipitation in the presence of ammonium chloride separates zirconium and other elements and an aliquot of filtrate is collected, equivalent to 0.2 g of sample. The ammonium salts are destroyed with nitric and hydrochloric acids and the calcium is determined with murexide. The high reagent blank is shown to be due to the reagent grade nitric acid, hydrochloric acid, and ammonium hydroxide.     

Atomic-absorption determination of copper impurities in zirconium salts using an air-acetylene flame

Summary An AAS method is described for the direct determination of traces of copper in zirconium(IV) oxide chloride and nitrate. An interference study of the zirconium matrix is reported. Best conditions for the removal of the suppressive effect of zirconium on the copper signal by addition of hydrofluoric acid are described. Results obtained by analyzing commercial samples from different manufacturers are presented.The author thanks Prof. P. Lanza for helpful discussions.     

微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定含铜污泥中多种重金属

为了填补现有方法的技术空白,本方法采用微波消解和电感耦合等离子体原子发射光谱法（ ICP-AES）相结合,实现对含铜污泥中铅、锌、铬、镉、砷、镁、铝、锑量的同时测定。首先采用盐酸-硝酸-氢氟酸微波消解进行样品的前处理,消解后加入高氯酸置于电热板进行除碳并赶酸,溶样效果理想,且有效避免了高温溶样对易挥发元素砷、锑的损失,整个过程安全、高效、无损。溶样后以电感耦合等离子体发射光谱法（ ICP-AES）进行测定。对含铜污泥的分解方法进行了合理选择,并对测定时的元素分析谱线及各测定元素间干扰情况等进行了讨论。该方法的加标回收率在95.31%~107.28%%,相对标准偏差（RSD）在0.31%~2.05%之间（n=7),结果表明,该方法准确度高,操作简单快捷,可同时测定多种元素,能满足批量的测定含铜污泥中铅、锌、镍、铁、镉、铬、砷、锑含量的测定要求。     

碘量法测定铜冶炼烟尘中铜

试验研究了铜冶炼烟尘中铜含量的测定方法,试料用盐酸、氢氟酸、硝酸、高氯酸及硫酸分解,氢溴酸除去砷、锡、锑,硫酸除去硒的干扰。进一步对滴定条件和共存元素的干扰及消除进行了试验,最终确定了最佳条件。按照实验方法测定6个铜冶炼烟尘样品中铜量,结果的相对标准偏差为0.22%~0.65%,精密度高,准确度好。样品加标回收率在98.92%~100.38%之间, 适用于铜冶炼烟尘中铜含量为5.00 %～65.00 %的测定。     

Electrochemical stripping determination of traces of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide

Procedures have been developed for the determination of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide, at concentrations of 1 ppm or less. Zirconium metal was dissolved in suphuric acid, and zirconium dioxide decomposed under pressure with hydrofluoric acid. Sample solutions were prepared in dilute sulphuric acid. For the stripping determination, the sample solution was either mixed with a complexing tartrate base electrolyte or the pre-electrolysis was carried out in acid solution, with the acid solution being exchanged for a pure base electrolyte (e.g. an acetate buffer) for the stripping step. The stripping step was monitored by d.c., differential pulse and Kalousek commutator voltammetry and the three methods were compared. A stationary mercury-drop electrode can generally be used for all the methods, whereas a mercury-film electrode is suitable only for the d.c. voltammetric determination of copper, lead and cadmium, as pulse measurements with films are poorly reproducible and the electrodes are easily damaged. The relative standard deviation does not exceed 20%. Some samples contained relatively large amounts of copper, which is best separated by electrodeposition on a platinum electrode.     

火焰原子吸收光谱法测定铜原矿尾矿中的镉

采用盐酸、氢氟酸、硝酸、高氯酸分步溶解的方式对具有硅、铁含量高等特性的铜原矿尾矿样品进行溶解。在体积分数为5%的盐酸介质中,利用原子吸收光谱法,采用扣除背景方式对样品溶液进行测定。样品溶解较完全,共存元素对镉的测定基本无干扰。方法重现性较好,准确度较高。相对标准偏差在2.3%~8.3%,加标回收率在96.7%~105%,标准样品分析结果与标准值基本一致。能满足日常分析检测的需要。     

Determination of selenium in soils by slurry-sampling graphite-furnace atomic-absorption spectrometry with polytetrafluoroethylene as silica modifier

A 6% slurry of polytetrafluoroethylene (PTFE) in 4% hydrofluoric acid and 1% nickel nitrate were used as modifiers for determination of selenium in soils by GF AAS. PTFE was used to remove silica from the soil sample, because this resulted in severe matrix effects. The temperature of fluorination, determined thermogravimetrically, was 600 degrees C. The yield of fluorination depends on the molar ratio of PTFE/silica, particle size, and the time and temperature of fluorination. The soil samples were pretreated with a small amount of concentrated hydrofluoric acid placed directly in the cup of autosampler. The results for the determination of selenium in the reference soil materials by means of the slurry-sampling technique and use of aqueous standards are in good agreement with the certified values.     

火焰原子吸收光谱法测定镍基高温合金中的镉

采用火焰原子吸收光谱法测定镍基高温合金中的镉,样品以硝酸-氢氟酸-水混合溶液(1+1+1)前处理,选择Cd 228.8nm为分析线进行测定,并通过标准加入法校正基体效应。考察了消解酸的选择,仪器工作参数的调整,基体和共存离子对镉测定的影响。结果表明,镍基高温合金中镉的检出限为0.088μg/g。加标回收率为94.1%～109%,结果的相对标准偏差(RSD,n=8)在0.54%～1.6%。方法操作简便、分析速度快、准确度好,适用于镉含量在0.0001%～0.001%的镍基高温合金中的测定。     

Semi-automated method for the determination of bismuth in rocks

A rapid and accurate method for the determination of bismuth in rock samples is described. Automated equipment is used to generate bismuth hydride from solutions of rock samples prepared by digestion with a mixture of hydrofluoric and perchloric acids. The evolved hydride is carried to a heated quartz tube by a stream of argon, and the atomic absorption of bismuth recorded. Thiosemicarbazide and 1,10-phenanthroline are used as masking agents to minimize interferences from copper and nickel. As little as 20 ng Bi g^-1 can be determined; the average r.s.d. is 5.4%. Results obtained for six USGS standard rocks are in close agreement with the recommended values obtained by an isotope dilution technique.