Direct analysis of powder samples using transversely excited atmospheric CO<Subscript>2</Subscript> laser-induced gas plasma at 1 atm

A novel method for the direct and sensitive analysis of powder samples has been developed by utilizing the characteristics of a transversely excited atmospheric (TEA) CO₂ laser. In this study, a powder sample was placed in a container and covered by a metal mesh; the metal mesh functions to control the blowing-off of the powder. The container was then perpendicularly attached on a metal surface. When a TEA CO₂ laser (1.5 J, 200 ns) was focused on the metal surface, a large hemispherical gas plasma (radius of around 8 mm) with long emission lifetime (several tens of microseconds) was produced without ablating the metal surface. The high-speed expansion force of the gas plasma samples the powder covered by the metal mesh and fine powder particles are sent into the gas plasma region to be dissociated and excited. Sensitive semi-quantitative analysis was made on organic powder samples such as powdered rice, starch, seaweed (agar), and supplements. The detection limit of heavy metals of Cr in powdered mineral supplement was approximately 0.55 mg/kg.     

Development of an ICP-IDMS method for accurate routine analyses of toxic heavy metals in polyolefins and comparison with results by TI-IDMS

An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method was developed as a suitable method – with respect to its sensitivity, precision, accuracy, and time-consumption – for the analysis of toxic heavy metal traces (Pb, Cd, Cr, and Hg) in polyolefins. Results for Pb, Cd, and Cr were compared with those obtained by thermal ionization isotope dilution mass spectrometry (TI-IDMS), which was used as a reference method. Because of its high first ionization potential and its high volatility mercury could not be determined by TI-IDMS. A multi-element spike solution, containing isotopically enriched ²⁰⁶Pb, ¹¹⁶Cd, ⁵³Cr, and ²⁰¹Hg, was used for the isotope dilution step. Decomposition of the polyolefin samples was carried out with concentrated HNO₃ at temperatures of about 300?°C in a high pressure asher (HPA). This procedure decomposes polyolefins completely and allows isotopic equilibration between sample and spike isotopes. Detection limits of 16 ng/g, 5 ng/g, 164 ng/g, and 9 ng/g were obtained for Pb, Cd, Cr, and Hg by ICP-IDMS using only sample weights of 0.25 g. In different commercially available polyethylene samples heavy metal concentrations in the range of < 5 ng/g to 4 × 10³ ng/g were analyzed. Both mass spectrometric methods were applied within the EU project “Polymeric Elemental Reference Material (PERM)” for the certification of two polyethylene reference materials. The ICP-IDMS results agreed very well with those of TI-IDMS which demonstrates the accuracy of the ICP-IDMS method also suitable for routine analyses.     

微波消解-ICP-OES法测定汽车涂料中8种重金属

建立微波消解-电感耦合等离子体发射光谱(ICP-OES)测定汽车涂料中Pb,Cr,Se,Ba,Sb,As,Cd,Hg含量的方法。以HNO_3-H_2O_2(体积比为4∶1)混合酸消解样品,各元素分析谱线:Pb 220.353 nm,Cr 267.716 nm,Se196.090 nm,Ba 233.527 nm,Sb 217.581 nm,As 189.042 nm,Cd 228.802 nm,Hg 184.950 nm。8种元素测定结果的相对标准偏差为2.02%~12.94%(n=6);对白色、蓝色、红色汽车漆样品进行加标回收试验,Pb,Cr,Se,Ba,As,Cd,Hg,的加标回收率为81.26%~99.79%,Sb的回收率为62.43%~87.61%。该方法快速、简便,精密度、准确度较高,可用于汽车涂料中重金属含量的监控。     

激光烧蚀-电感耦合等离子体质谱法测定塑料中的Pb、Cd、Cr和Hg

采用激光烧蚀固体进样技术的电感耦合等离子体质谱法(LA-ICP-MS)测定了塑料中的Pb、Cd、Cr和Hg。选择了线扫描激光烧蚀方式,并从灵敏度和稳定性角度优化了工作参数。根据计算分馏因子考察了分馏效应,结果表明,所测元素分馏效应小。塑料中Hg的记忆效应严重,认为主要来自样品表面吸附,减小样品的表面积可减小Hg的记忆效应。以聚丙烯标准物质及其空白片作校准曲线,应用于ABS、PPS、PA66+30%GF、PVC、PTFE等实际塑料样品的测定,测定结果与ICP-OES(XRF)法测定值基本吻合。Pb、Cd、Cr和Hg的检测下限分别为0.002、0.001、0.08和1.5 mg/kg。     

Chemically-modified activated carbon with ethylenediamine for selective solid-phase extraction and preconcentration of metal ions

A new method that utilizes ethylenediamine-modified activated carbon (AC-EDA) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The new sorbent was prepared by oxidative surface modification. Experimental conditions for effective adsorption of trace levels of Cr(III), Fe(III), Hg(II) and Pb(II) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4.0. Complete elution of absorbed metal ions from the sorbent surface was carried out using 3.0 mL of 2% (%w/w) thiourea and 0.5 mol L⁻¹ HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.4, 28.9, 60.5 and 49.9 mg g⁻¹ for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The time for 94% adsorption of target metal ions was less than 2 min. The detection limits of the method was found to be 0.28, 0.22, 0.09 and 0.17 ng mL⁻¹ for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The precision (R.S.D.) of the method was lower 4.0% (n = 8). The prepared sorbent as solid-phase extractant was successfully applied for the preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) in natural and certified samples with satisfactory results.     

Novel Chelating Resin for Solid-Phase Extraction of Metals in Certified Reference Materials and Waters

A new chelating resin, poly(diacetonitrile methacrylamide-co-divinylbenzene-co-vinylimidazole), was synthesized and characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and elemental analysis. The novel resin was used for the first time as a chelating adsorbent for the preconcentration of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn from various samples by flame atomic absorption spectrometry. The adsorption capacities of the resin were 29.3, 31.6, 29.3, 27.3, 35.5, 31.7, 39.8, and 32.3?mg?g^?1 for Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn, respectively. The detection limits of the metal ions were from 0.42 to 3.21?µg?L^?1. A preconcentration factor of 30 for all metal ions was obtained. The precision of the method as the relative standard deviation was less than or equal to 2.6%. The described method was validated with certified reference materials and fortified real samples. The method was used for the determination of the analytes in well water and wastewater.     

Development of an ICP-IDMS method for accurate routine analyses of toxic heavy metals in polyolefins and comparison with results by TI-IDMS

An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method was developed as a suitable method - with respect to its sensitivity, precision, accuracy, and time-consumption - for the analysis of toxic heavy metal traces (Pb, Cd, Cr, and Hg) in polyolefins. Results for Pb, Cd, and Cr were compared with those obtained by thermal ionization isotope dilution mass spectrometry (TI-IDMS), which was used as a reference method. Because of its high first ionization potential and its high volatility mercury could not be determined by TI-IDMS. A multi-element spike solution, containing isotopically enriched 206Pb, 116Cd, 53Cr, and 201Hg, was used for the isotope dilution step. Decomposition of the polyolefin samples was carried out with concentrated HNO3 at temperatures of about 300 degrees C in a high pressure asher (HPA). This procedure decomposes polyolefins completely and allows isotopic equilibration between sample and spike isotopes. Detection limits of 16 ng/g, 5 ng/g, 164 ng/g, and 9 ng/g were obtained for Pb, Cd, Cr, and Hg by ICP-IDMS using only sample weights of 0.25 g. In different commercially available polyethylene samples heavy metal concentrations in the range of < 5 ng/g to 4 x 10(3) ng/g were analyzed. Both mass spectrometric methods were applied within the EU project "Polymeric Elemental Reference Material (PERM)" for the certification of two polyethylene reference materials. The ICP-IDMS results agreed very well with those of TI-IDMS which demonstrates the accuracy of the ICP-IDMS method also suitable for routine analyses.     

电感耦合等离子体原子发射光谱法测定塑胶中镉、铅、汞、铬含量的不确定度

对电感耦合等离子体发射光谱法测定塑胶中镉、铅、汞、铬含量的不确定度进行了评定.分析了测定过程中不确定度的主要来源,对各不确定度分量进行了量化.镉、铅、汞、铬的合成标准不确定度分别为0.146、2.27、1.71、1.06 mg/kg.     

湖北典型地区茶叶-土壤重金属相关性研究

本文旨在分析湖北典型地区茶叶以及土壤中各种元素的含量,采用原子荧光法(AFS)和电感耦合等离子体质谱法(ICP-MS)等方法对135对茶叶及土壤样品进行测定,并探讨各种元素之间的相互关系和影响。研究结果表明,土壤中元素的分布对茶叶中元素含量分布有一定意义,典型区土壤养分有效磷和碱解氮较丰富,有机质和速效钾较缺乏。典型区茶叶作物表层土壤 Cd、Pb、Cu、Cr、As 均存在不同程度的超标。土壤 Cd 和 Hg 的污染指数高,潜在生态风险强。典型区茶叶可食部分重金属含量均值依次为 Cu>Pb>Cd>Hg>As>Cr,重金属元素在茶叶中含量均为中等变异性。 茶叶对 Cu、Pb 的富集系数明显高于 Hg、As、Cd、Cr,不同茶叶对同一元素的富集能力存在差异。土壤重金属含量与土壤 pH 值、CEC、有效磷、总氮等理化指标关系密切。茶叶重金属含量与土壤重金属含量水平相关性较弱,但与茶叶对重金属的富集能力均呈显著正相关关系。     

Determination of Hg,As, Pb,and Cd in Orchard Soils by Sequential Injection Vapor Generation Atomic Fluorescence Spectrometry

An analytical procedure was developed for determination of Hg, As, Pb, and Cd in soil samples using sequential injection vapor generation atomic fluorescence spectrometry (SI-VG-AFS) with sample preparation by microwave digestion system. The effects of analytical conditions on the fluorescence intensity were investigated and optimized. Under the optimized condition, the detection limits of the method were 5, 68, 40, and 3 ng L^?1 for Hg, As, Pb, and Cd, respectively. The accuracy of method was verified by the determination of the certified reference soil, and the recoveries for Hg, As, Pb, and Cd were in the range of 98.7–106.1%. The proposed method has been successfully applied to determine the heavy metals in navel orange orchard soils in Ganzhou, and the environmental quality of the orchard soils was assessed based on the content of the heavy metals. According to the second criterion of environmental quality standard for soils, Pb content in all soil samples collected from the orchards of 18 districts were within safe limits, but a few orchards were slightly contaminated with Hg, As, and Cd. Comparison of heavy metal mean concentrations with the safe limits of environmental quality standard for soils, the quality of Ganzhou navel orange orchard soils were in line with the request of the green food production base.     

Determination of trace elements in marine plankton by inductively coupled plasma mass spectrometry (ICP-MS)

A method has been developed for the determination of 23 elements in marine plankton in which inductively coupled plasma (ICP) source mass spectrometry (MS) was used to quantify the elements in the solution after digestion in a mixture of hydrofluoric and nitric acids in sealed PTFE vessels in a microwave field. The procedure was validated by the analysis of a standard reference soil (SRM 2709 San Joaquin Soil) and a standard reference fresh water plankton (CRM 414). The method was applied to the analysis of several marine plankton samples grown under controlled conditions including several whose growth media had been enriched with selenium. Matrix induced signal suppressions and instrumental drift were corrected by internal standardization. The suitabilities of germanium, indium, rhodium, scandium and yttrium as internal standard elements were evaluated. Neither scandium nor yttrium could be used due to the presence of these elements in the samples, germanium was used for the determination of As, Co, Cu, Fe, Ni, Se, Si and Zn, indium was used for Al, Ba, Ca, Eu, Sr, and Tl, and rhodium was used for Cd, Cr, Hg, Mg, Pb, Sb, Sn, and V. For Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Si, Sr, V, and Zn internal standardization did not completely compensate for the suppressive effect of the heavier elements and the solutions were diluted. However, for As, Ba, Cd, Co, Eu, Hg, Pb, Sb, Se, Sn and Tl, it was possible to obtain accurate results despite the 35–¶40% suppression in the signals. Isobaric overlap was only a problem in the cases of ⁴²Ca and ⁷⁸Se; ⁴⁴Ca and ⁷⁷Se, respectively, were used. Memory effects were only observed with Hg for which a nitric acid-sodium chloride solution was the most effective wash-out solution. The marine plankton samples were able to tolerate a higher concentration of Hg as the selenium concentration increased.     

A study of the direct determination of Cd, Cr, Cu, Pb and Zn in certified reference materials of soils by solid sampling electrothermal atomic absorption spectrometry

A simple and rapid method for the direct determination of Cd, Cr, Cu, Pb and Zn in soil was developed. The method was developed using three certified reference materials of soil: Eutric Cambisol, Orthic Luvisols and Rendzina, which differed in their matrix composition. Chemical modifiers were essential to achieve reproducible and interference-free signals for the analytes studied. The best results were obtained with a Pd/Mg(NO₃)₂ admixture for the determination of Cd, Pb and Zn and NH₄F for Cu. The combination of W (as a permanent modifier) and Mg(NO₃)₂ provided well-defined signal profiles for Cr. The following spectral lines were used: Cd 228.8 nm, Cr 520.6 nm, Cu 218.2 nm, Pb 205.3 nm and Zn 307.6 nm. The limit of detection was 4.2 ng g^− 1 for Cd, 1.1 μg g^− 1 for Cr, 0.5 μg g^− 1 for Cu, 1.3 μg g^− 1 for Pb and 8.6 μg g^− 1 for Zn for the maximum sample mass used. Under optimized conditions, the analyte and matrix were separated effectively in situ, and aqueous standards could be used for calibration.     

Direkte spektroskopische Analyse von Spurenelementen in ZnSe-Proben im rotierenden Gleichstrombogen unter Anwendung eines homogenen Magnetfeldes und von Zusatzsubstanzen

Summary An emission spectroscopic method was developed for the simultaneous determination of the trace elements Ag, Al, Cr, Cu, Fe, Ga, In, Mg, Mn, Ni, Pb and Ti in ZnSe samples. The sample to be analysed (about 10 mg) is vaporized directly from the anode and excited by a rotating d.c. arc using a homogeneous magnetic field. The influence of elements with lower ionization potential on the plasma was investigated, too. These additives (NaCl, KCl) were introduced into the plasma by means of a wick electrode (cathode). The calibration is carried out on the basis of mixtures of oxides of the trace elements with spectroscopically pure ZnSe powder. Analytical detection limits of the trace elements investigated were in the region of ppm and sub-ppm corresponding to absolute amounts of 10 ng and lower.     

Elemental Analysis of Phytotherapeutic Products by Inductively Coupled Plasma–Tandem Mass Spectrometry

A procedure for the determination of As, Cd, Cr, Ni, Pb, and V in phytotherapy medicines by inductively coupled plasma–tandem mass spectrometry is reported. The use of tandem mass spectrometry with oxygen into an octopole reaction system at various gas flow rates and the combination of on-mass and mass-shift modes was evaluated. Cadmium, Cr, Ni, and Pb were determined as free atomic ions while As and V were determined as the oxides AsO⁺ and VO⁺ in the same run. Samples were prepared by microwave-assisted digestion with dilute nitric acid and hydrogen peroxide. Two plant-certified reference materials (apple leaves and tomato leaves) were used to check the accuracy. For tandem mass spectrometry with 0.5?mL min^?1 O₂, recoveries in the 85–113% were typically obtained and no statistical differences were observed at the 95% confidence level (t-test) in comparison with the certified values. Using these conditions, the limits of detection for the method were 0.01, 0.0002, 0.008, 0.008, 0.003, and 0.002?µg g^?1 for As, Cd, Cr, Ni, Pb, and V, respectively. The procedure was used for the analysis of four phytotherapic drugs and the determined concentrations were up to 0.168?µg g^?1 As, 0.03?µg g^?1 Cd, 0.82?µg g^?1 Cr, 1.18?µg g^?1 Ni, 0.52?µg g^?1 Pb, and 2.4?µg g^?1 V with average precision values of 8% as the relative standard deviation. The found concentrations were compared with limits proposed in official guidelines and, in most cases, the values were below the maximum limits allowed.     

Simultaneous determination of Cd,Cr, Cu,Ni, Pb and Zn in sewage sludge by slurry introduction ICP-OES method

In order to evaluate the slurry nebulisation method as an alternative method for analysis of sewage sludge, the metal content of sludge samples of different origins was determined. The concentrations of six elements: Cd, Cr, Cu, Ni, Pb, and Zn were determined by introducing the sludge as a slurry into an inductively coupled plasma optical emission spectrometer (ICP-OES). Calibration was performed by using aqueous standard solutions. For comparison, the sewage sludge was also digested by microwave digestion and introduced into the plasma as an aqueous solution. The accuracy of the method was checked by analysing a sewage sludge certified reference material (CRM 007-040 Sewage Sludge). The Student's t-test showed that values obtained using slurry nebulisation were close to the certified values at a 95% confidence level. The values of elements Cd 11.1?±?0.8; Cr 37.7?±?3.3; Cu 563.3?±?38.4; Pb 119.2?±?10.1; Zn 729?±?68.2?mg?kg^?1 obtained using this method were comparable with those obtained using the conventional method. The slurry method can, therefore, be successfully applied to the determination of content of each element in sewage sludge with RSD less than 3%, without the need to predissolve them. This could avoid the use of hazardous chemicals, incomplete dissolution and loss of volatile analytes.     

Preparation of sinapinaldehyde modified mesoporous silica materials and their application in selective extraction of trace Pb(II)

A new solid phase extractant, sinapinaldehyde (SA) modified SBA-15 mesoporous silica, was developed for selective extraction and preconcentration of trace Pb(II) from aqueous solutions. The successful immobilization of SA on SBA-15 and the strong interaction between SA-SBA-15 and Pb(II) were characterized and confirmed by FTIR spectroscopy and scanning electron microscopy. Parameters such as solution pH, shaking time, eluent condition and sample volume were optimized so that the maximum removal of Pb(II) from solution could be achieved. At pH 4.0, the maximum adsorption capacity of the sorbent for Pb(II) was found to be 33.6?mg?g^?1 and the adsorbed Pb(II) could be completely eluted using a mixed solution of 2?M HCl and 5% CS(NH₂)₂. Some common metal ions such as K(I), Na(I), Mg(II), Ca(II), Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) did not interfere with the adsorption of trace Pb(II). The detection limit of the present method was found to be 1.3?ng?mL^?1 and the relative standard deviation was less than 2.0% (n?=?8). These results suggested that this new sorbent is very efficient and selective for the removal of trace Pb(II) in water samples.     

某冶炼厂周边土壤重金属污染评价分析及源解析研究

有色金属矿产资源采选冶活动造成的土壤重金属污染已成为严重的环境问题。采用电感耦合等离子体质谱法和光谱法测定某冶炼厂周边不同区域内土壤中重金属Cu、Pb、Zn、As、Ni、Cr、Cd、Hg元素含量,采用Kriging空间插值方法对重金属空间分布特征进行分析,采用内梅罗指数法对其污染状况进行评价,采用多元统计分析对重金属元素的污染源进行分析。结果表明,研究区土壤采样点80%处于污染状态,且以重度污染为主,污染比较严重的区域受风向影响在冶炼厂的西部和南部方向,污染严重的重金属元素为Cu、Pb、Cd、Zn和As,土壤中各重金属元素的污染源除来自于冶炼厂外,Zn-Cd-PbCu-As、Ni-Cr、Hg分别还受到机动车辆排放、自然因素、燃煤及农药使用的影响。     

Determination of Essential and Toxic Elements in Vegetables from South Korea

This study reports the determination of trace essential (Co, Cr, Cu, Se, and Zn) and toxic (Al, As, Cd, Hg, and Pb) elements in greenhouse tomatoes, peppers, and cucumbers from supermarkets of Seoul, Busan, Gangneung, Daegu, Daejeon, and Gwangju, South Korea using inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, and direct mercury analysis. The methods were validated by linearity, limits of detection and quantification, precision, accuracy, and recovery measurements that provided satisfactory results in all cases. Among the essential trace elements, Zn was found to have the highest concentrations (0.84–2.5?mg/kg) followed by Cu (0.21–0.62?mg/kg) and Cr (0.01–0.06?mg/kg). The mean concentrations (mg/kg) of the toxic elements were in the order Al?>?Pb?>?As?>?Cd?>?Hg for tomatoes and cucumbers and Al?>?Pb?>?Cd?>?As?>?Hg for peppers; all were below the permissible limits set by World Health Organization for human consumption. The estimated dietary intake, target hazard quotients (THQs), and hazard indices of the samples were within safe levels. The combined THQ values for the toxic elements in the vegetables were from 0.002 to 0.012 with significant contribution from arsenic, aluminum, cadmium, and mercury. The results of this study show that trace and toxic elements in the analyzed vegetables do not impose any serious health harmful effects for the population upon consumption.     

Assessment of the health of a river ecosystem due to the impact of pollution from industrial discharge using instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry

Inductively coupled plasma-mass spectrometry (ICP-MS) and neutron activation analysis (NAA) were employed in the determination of heavy metal concentrations in water, plant and sediment samples to assess the extent of heavy metal pollution in a river system which is located within an industrial zone. Elemental concentrations of As, Pb, Hg, Cr, Cu, Cd, Ni and Zn were measured in the samples. Statistical analysis was performed on the data obtained to look for trends in the pollution pattern of these elements on the river system. The trend in concentrations of heavy metals pollution in water samples is in the order of Zn > Cu > Ni > Cr > As > Pb > Hg > Cd, whereas in plants the order is Zn > Cr > Cu > Pb > Ni > As > Hg > Cd and in sediments Zn > Cu > Pb > Ni > As > Hg.     

灯盏花中重金属元素的化学形态及分布

应用火焰原子吸收光谱法(测定铅、铬、镉)及原子荧光光谱法(测定汞、砷)对灯盏花中重金属的化学形态及其分布进行了研究。0.5g经过预处理的试样用浓硝酸消解并经高氯酸冒烟至近干,用水溶解残盐并定容为25mL。在此溶液中分别用上述两方法测定5种金属元素的总量。分别用5种不同萃取溶剂,即乙醇-水(80+20)混合溶液、亚沸重蒸馏水、1mol·L-1氯化钠溶液、乙酸(2+98)溶液及0.6mol·L-1盐酸溶液,对10g试样进行连续超声萃取。各次所得萃取液分别用硝酸和高氯酸按上述方法处理后测定其中5种金属的含量。文中给出了上述金属元素在各种化学形态中的含量及分布状态,此次结果对评价中草药的生物功能及毒性能有参考价值。