微波消解-原子吸收光谱法测定蚕蛹中的微量元素

分别采用FAAS和GFAAS方法,测定蚕蛹样品中的常见微量元素及有害重金属元素。对微波消解条件和测定方法进行了探讨和优化,并用标准物质贻贝验证,获得较满意的准确度和精密度。方法可用于蚕蛹样品及同类产品的微量元素元素测定。     

Advantages of the iridium permanent modifier in fast programs applied to trace-element analysis of plant samples by electrothermal atomic absorption spectrometry

The application of a fast program combined with the advantages of the iridium permanent modifier is proposed for trace element analysis of plant samples by electrothermal atomic absorption spectrometry (ETAAS). For two volatile elements (Cd, Pb) and two mid-refractory elements (Cr, Ni) it was demonstrated that coating of the platform or of the tube atomization area with Ir is an efficient means of improving the accuracy and precision of results. A detailed study of interference from individual main matrix components and from composite plant matrices has confirmed the usefulness of the whole approach. The validity of the method has been confirmed by analysis of eight reference plant materials.     

Advantages of the iridium permanent modifier in fast programs applied to trace-element analysis of plant samples by electrothermal atomic absorption spectrometry

The application of a fast program combined with the advantages of the iridium permanent modifier is proposed for trace element analysis of plant samples by electrothermal atomic absorption spectrometry (ETAAS). For two volatile elements (Cd, Pb) and two mid-refractory elements (Cr, Ni) it was demonstrated that coating of the platform or of the tube atomization area with Ir is an efficient means of improving the accuracy and precision of results. A detailed study of interference from individual main matrix components and from composite plant matrices has confirmed the usefulness of the whole approach. The validity of the method has been confirmed by analysis of eight reference plant materials.     

Performance of NAA Methods in an International Interlaboratory Reference Material Characterization Campaign

An extensive database of analytical results from a recent biological matrix Reference Material Characterization Campaign permitted an intercomparison of the performances of various methods among each other and with "true" best estimate concentration values established for these materials. Six different variants of neutron activation analysis (NAA) methods were employed including: instrumental neutron activation analysis, instrumental neutron activation analysis with acid digestion, neutron activation analysis with radiochemical separation, neutron capture prompt gamma activation analysis, epithermal instrumental neutron activation analysis, and neutron activation analysis with preconcentration. The precision and accuracy performance of NAA-based analytical methods are compared with three other major techniques, atomic absorption spectrometry (AAS), atomic emission spectrometry (AES) and mass spectrometry (MS) for 28 elements in 10 natural matrix materials.     

Preconcentration of trace elements in potable liquids by means of a liquid membrane emulsion for flame atomic absorption determination

Summary A liquid membrane emulsion was developed for the simultaneous extraction and preconcentration of traces of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn in potable liquids. After preconcentration, the eight elements were determined by flame atomic absorption spectrometry (FAAS). The results of analyses of potable water, beer and soft drinks, each from five or six different sources are listed. Data from the preconcentration method were compared with corresponding data obtained from the direct determination of the elements by graphite furnace atomic absorption spectrometry (GFAAS). Differences in results for trace elements between the liquid membrane emulsion-FAAS method and the GFAAS method were in the ranges of ±10% (water), ±9% (beer) and ±14% (soft drinks) for most of the trace elements. The satisfactory agreement meant that analyses of such liquids for trace elements can be carried out accurately with less expensive and widely available FAAS equipment.     

4种保健野菜中微量元素的测定

以茵陈、牛繁缕、曲曲菜、猪毛菜为材料,用原子吸收光谱法测定了4种野菜中的Ca、Mg、Cu、Zn、Fe、Mn 6种微量元素的含量。结果表明,4种野菜中含有丰富的人体必需微量元素,6种元素的加标回收率在96.57%～99.06%之间,相对标准偏差RSD值均低于3%,说明本试验测定结果可靠,精密度高。     

Determination of some trace elements in food and soil samples by atomic absorption spectrometry after coprecipitation with holmium hydroxide

The determination of trace elements in food and soil samples by atomic absorption spectrometry was investigated. A coprecipitation procedure with holmium hydroxide was used for separation-preconcentration of trace elements. Trace amounts of copper(II), manganese(II), cobalt(II), nickel(ll), chromium(lll), iron(Ill), cadmium(ll), and lead(ll) ions were coprecipitated with holmium hydroxide in 2.0 M NaOH medium. The optimum conditions for the coprecipitation process were investigated for several commonly tested experimental parameters, such as amount of coprecipitant, effect of standing time, centrifugation rate and time, and sample volume. The precision, based on replicate analysis, was lower than 10% for the analytes. In order to verify the accuracy of the method, the certified reference materials BCR 141 R calcareous loam soil and CRM 025-050 soil were analyzed. The procedure was successfully applied for separation and preconcentration of the investigated ions in various food and soil samples. An amount of the solid samples was decomposed with 15 mL concentrated hydrochloric acid-concentrated nitric acid (3 + 1). The preconcentration procedure was then applied to the final solutions. The concentration of trace elements in samples was determined by atomic absorption spectrometry.     

火焰原子吸收法测定茶叶中的微量元素

使用同一消化液,溶解消化样品,以稀盐酸为底液,火焰原子吸收分光光度法对茶叶中Mn、Fe、Zn、Cu、Pb五种微量元素进行了测定。结果表明,标准曲线线性关系良好(r＞0．999)、精密度和准确度均较好,能够达到分析要求。     

A clean up step of fat content previous to trace metal characterization in mussel tissues by inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry analysis of trace and major elements of mussel tissues can be quickly and accurately analyzed after cleaning up the interfering fat content before the sample is digested in a microwave oven. Making use of experimental designs, the clean up procedure was achieved by the extraction of 1 g of freeze-dried tissue sample stirred with 5 ml of dichloromethane during five minutes. The microwave assisted digestion of the fat free samples was carried out with 0.2 g of tissue sample, 15 ml of 7.0% nitric acid with a power of 980 W during 18 min. The analytical method efficiency (accuracy and precision) was evaluated with a CRM: (NIST 2977, mussel tissue) and real mussel samples analyzed previously. The results confirmed the accuracy of the analysis by agreement with the previous results but the precision was significantly improved. The developed method allows operating routinely permitting to large numbers of samples to be quickly screened for trace metals.     

Developing electrodeposition techniques for preconcentration of ultra-traces of Ni, Cr and Pb prior to arc-atomic emission spectrometry determination

Electrodeposition is known to be proper for separation and preconcentration of extremely low concentrations of analytes from the bulk sample which is instrumentally very simple. In the present research, a combination of electrodeposition with arc atomic emission spectrometry (ED-AAES) method has been developed in order to improve the analytical performance of this spectrometry technique. The results show that sensitivity and detection limits by using ED-AAES were improved 1000–2000 folds over those of normal arc atomic emission spectrometry in determination of the selected elements. The detection limits for measurement of Ni, Cr and Pb were 2.56, 3.05 and 2.11 µg L^{− 1} for monodeposition and 3.31, 3.72 and 3.25 µg L^{− 1} for simultaneously deposition, respectively. The precision of determination was in the range of 2–4% RSD. Typical calibration graphs for these elements were linear up to 100 µg L^{− 1}, depending on the element and matrix.Application of this technique was also tested on determination of the studied elements in an electroplating plant's waste water. The accuracy of technique was verified by comparing the results of the waste water analysis with those of electrothermal atomic absorption spectroscopy as a reference standard method.The obtained results show that the combined technique (ED-AAES) has been progressed substantially toward the ultimate goal of direct interference-free determination of trace analysis in complex samples by AAES.     

Derivative flame atomic absorption spectrometry and its application in trace analysis

Flame atomic absorption spectrometry (FAAS) is an accepted and widely used method for the determination of trace elements in a great variety of samples. But its sensitivity doesn’t meet the demands of trace and ultra-trace analysis for some samples. The derivative signal processing technique, with a very high capability for enhancing sensitivity, was developed for FAAS. The signal models of conventional FAAS are described. The equations of derivative signals are established for FAAS, flow injection atomic absorption spectrometry (FI-FAAS) and atom trapping flame atomic absorption spectrometry (AT-FAAS). The principle and performance of the derivative atomic absorption spectrometry are evaluated. The derivative technique based on determination of variation rate of signal intensity with time (dI/dt) is different from the derivative spectrophotometry (DS) based on determination of variation rate of signal intensity with wavelength (dI/dλ). Derivative flame atomic absorption spectrometry (DFAAS) has higher sensitivity, lower detection limits and better accuracy. It has been applied to the direct determination of trace elements without preconcentration. If the derivative technique was combined with several preconcentration techniques, the sensitivity would be enhanced further for ultra-trace analysis with good linearity. The applications of DFAAS are reviewed for trace element analysis in biological, pharmaceutical, environmental and food samples.     

Inductively coupled plasma-mass spectrometry: Capabilities and applications

Researchers in the field of trace elements analysis are continuously in search of new instrumental solutions for obtaining better results in terms of analysis speed, precision, accuracy, detection power, and applicability to a wider range of analytical problems. One of the more recent innovations in this field is the inductively coupled plasma (ICP) source coupled with a mass spectrometry (MS). An ICP-MS system consists of an ICP torch which ionizes the species present and a mass spectrometer for the separation under vacuum of the different species. The main advantages of this technique with respect to graphite furnace atomic absorption spectrometry (GFAAS) and to ICP atomic emission spectrometry (ICP-AES) are: (a) detection limits better than those obtained with graphite furnace, i.e., down to the ng g⁻¹ level, due to the high sensitivity of the channel electron multiplier, which transforms the mass of each ion into an electric signal; (b) the possibility of detecting refractory elements, lanthanides, and all the other elements including halogens, C, and S; (c) high analysis speed (up to 90 elements in 5 min) due to the velocity of the quadrupole mass spectrometer in selecting different masses with respect to the speed necessary to scan different wavelengths; (d) spectral simplicity, because spectra have peaks only at the mass of each isotope and all elements have at least one isotope free from spectral overlap of other analytes; (e) capability of determining individual isotopes of each element. The instrument, therefore, allows not only quantitative elemental analyses to be carried out, but also semiquantitative assays of all the elements present and isotopic ratio analyses to determine quantitatively two or more isotopes of the same element. The most interesting application fields of this technique are in environmental chemistry, geochemistry, oil chemistry, technology of semiconductors, and biochemistry.     

氢化物发生-原子荧光光谱法同时测定高纯铟中As、Sb

研究了氢化物发生-原子荧光光谱法测定高纯铟中微量As、Sb元素的条件,选择了适宜的反应条件以及仪器的最佳工作条件,考察了铟基体对被测元素的干扰,采用基体匹配的方法消除干扰,建立了氢化物发生-原子荧光光谱法测定高纯铟中微量的As、Sb的分析方法。As、Sb的检出限分别为0.18和0.28 ng/mL,测定下限为1.2×10-5和1.9×10-5,相对标准偏差分别为1.9%和1.7%,回收率为97.4%和103%,适用于5～6 N高纯铟中微量As、Sb的测定。     

Line selection and interference correction for the analysis of tungsten alloy by inductively coupled plasma atomic emission spectrometry

A method for the analysis of tungsten alloy to determine selected elements using inductively coupled plasma atomic emission spectroscopy is described, with emphasis on line selection and spectral interference. The spectral interference coefficients were calculated for the spectral lines of selected major and trace elements. These values were used to select analytical lines and to calibrate concentrtions of the analytes. The detection limits of the elements for this method were determined and compared with those obtained by flame atomic absorption spectrometry and direct current carbon are emission spectrometry. The results indicated that the detection limits for all of the elements determined by the proposed method are significantly better than those obtained by other techniques. In this study, the analytical reliability of the proposed method was estimated by comparison of the analytical data for the two types of tungsten alloys produced by the Korean Tungsten Company with those obtained by the matrix matching method and the results indicated that the accuracy of multi-element analysis is satisfactory.     

Intercomparison of five methods for the determination of trace metals in sea water

Trace elements (Mn, Fe, Co, Zn, Ni, Cu and Cr) were preconcentrated from sea water by retention on Chelex-100 resin, APDC/8-quinolinol complexation followed by extraction with 4-methyl-2-pentanon or Freon-113, or coprecipitation with Mg(OH)₂ or Fe(OH)₂. After consideratin of analytical blanks, extraction efficiency, precision preconcentration factor, and suitability for operation on board ship, the best results were obtained by preconcentrating Mn, Fe, Co, Zn, Ni and Cu on Chelex-100 resin and coprecipitation of chromium(III) and (VI) with Fe(OH)₂. Graphite-furnace atomic absorption spectrometry and inductively-coupled plasma atomic emission spectrometry were used for the final measurements. The accuracy of the method was tested by using the reference sea water sample NASS-1.     

火焰原子吸收光谱法测定茯苓中微量元素

本文确定了各微量元素火焰原子吸收光谱仪的工作条件,建立了各微量元素线性回归方程.应用火焰原子吸收光谱法测定了天然茯苓和液体发酵茯苓中微量元素含量.研究结果表明二者微量元素含量存在一定的差异,探讨了产生上述差异的原因.     

Chemometric investigation of systematic error in the analysis of biological materials by flame and electrothermal atomic absorption spectrometry

Systematic errors observed when using flame atomic absorption spectrometry (FAAS) and electrothermal atomic spectrometry (ETAAS) for the analysis of biological solid materials (seafood products) were evaluated. The effect of the sample pre-treatment method (microwave-assisted acid digestion, ultrasound-assisted acid leaching and slurry sampling) as well as the number of times that a certain pre-treatment process is repeated, were two factors evaluated. They give information about the effect of the sample pre-treatment on the uncertainty in the analysis. In addition, the number of measurements (i.e., number of times that an acid digest, an acid leachate or aqueous slurry are analysed) and the calibration technique used (aqueous calibration method or standard addition technique) were other two variables taken into account. This last factor gives information about the effect of the calibration on the results, while the replicate measurements showed the repeatability. A fifth variable named as sample matrix tests the influence of the matrix sample on the systematic error through the use of different reference materials. This variable allows the study of the effect of the trace element concentrations on the uncertainty because the trace elements contents are different in each reference material. Experimental design and principal component analysis approaches were used as chemometric tools. It has been found that the use of the slurry sampling technique in ETAAS and FAAS and the determination of high element concentrations by ETAAS have led to poor precision.     

二苯硫脲-醋酸丁酯萃取-石墨炉原子吸收法测定地球化学样品中痕量银

对石墨炉原子吸收光谱法测定地球化学样品中痕量银进行了研究。样品经盐酸、硝酸、硫酸、高氯酸溶解,在盐酸(1.2mol/L)介质中用醋酸丁酯萃取银与二苯硫脲螯合物,用石墨炉原子吸收光谱法测定地球化学样品中痕量银,方法检出限为0.011ng/mL,相对标准偏差(RSD,n=11)为6.0%~12.2%,加标回收率为96.00%~105.00%。能满足地球化学样品中银含量为0.02~5μg/g范围内银测定的准确度和精密度的要求。     

Determination of trace elements in biological materials using tetramethylammonium hydroxide for sample preparation

A method to prepare milk powder, bovine liver and bovine muscle samples for analysis by electrothermal atomic absorption spectrometry (ETAAS) is proposed. Samples are mixed with a small amount of tetramethylammonium hydroxide (TMAH) and a stable and homogeneous slurry is produced in ca. 2 h with heating at 60–70 °C. After such sample preparation and dilution with water, trace elements are determined in certified reference materials. Pyrolysis and atomisation temperatures are optimised for each element, and several modifiers are investigated. External calibration is used for every analyte. Limits of detection (LODs), precision and accuracy are reported for Cd, Pb, Ni, Cr, Cu and Ag and compared with those obtained after conventional acid digestion. The main advantages of the proposed method are the simplicity of sample preparation and the longer lifetime of the graphite tube.