低压微波消解─ICP-AES法测定聚氯乙烯塑料及其制品中的Pb、Cd、Cr和Hg

采用低压微波消解系统,以HNO3、HCl、H2O2、HClO4和HF消解样品,用H3BO3络合过量的F-,并研究了Cl-对测汞的影响、共存元素的干扰、H3BO3对各元素的影响,建立了低压微波消解─ICP-AES法测定聚氯乙烯塑料及其制品中Pb、Cd、Cr和Hg的方法。Pb、Cd、Cr和Hg的检出限(3σ)分别为:0.012、0.002、0.006、0.020μg/mL,相对标准偏差为0.5%~4.0%,回收率为95%~101%。该方法可推广应用到其它塑料中Pb、Cd、Cr和Hg的测定,已应用于实际的检测工作。     

低压微波消解——ICP-AES法测定聚氯乙烯塑料及其制品中的Pb、Cd、Cr和Hg

采用低压微波消解系统, 以HNO3、HCl、H2O2、HClO4和HF消解样品, 用H3BO3络合过量的F-, 并研究了Cl-对测汞的影响、共存元素的干扰、H3BO3对各元素的影响, 建立了低压微波消解─ICP-AES法测定聚氯乙烯塑料及其制品中Pb、Cd、Cr和Hg的方法. Pb、Cd、Cr和Hg的检出限(3σ)分别为: 0.012、0.002、0.006、0.020 μg/mL, 相对标准偏差为0.5%～4.0%, 回收率为95%～101%. 该方法可推广应用到其它塑料中Pb、Cd、Cr和Hg的测定, 已应用于实际的检测工作.     

激光剥蚀电感耦合等离子体质谱在涂料重金属分析中的应用

将激光剥蚀进样技术(LA)与ICP-MS检测器联用,并将这一新技术应用在涂料重金属元素的检测上,通过优化LA和ICP-MS参数,并采用双气流校正技术,以13C、103Rh为双内标,有效地改善了信号强度和稳定性,同时对Hg的记忆效应进行研究,最终建立了LA-ICP-MS法测定涂料中Cr、As、Cd、Sn、Sb、Hg、Pb元素的定量分析方法,样品测定结果与湿法消解ICP-OES法基本吻合。     

微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定ABS塑料中Pb、Cd、Hg

以ABS塑料为研究对象,采用微波消解法进行样品的前处理,使用电感耦合等离子体原子发射光谱(ICP-AES)法测定ABS塑料中Pb、Cd、Hg,结果表明,Pb、Cd、Hg加标回收率均在95.0%～105%,测定相对标准偏差(RSD)均小于3%,方法在缩短样品前处理时间的同时得到较高的元素消解回收率和较为理想的精密度,适用于ABS塑料中重金属含量的快速测定。     

微波消解ICP-AES法测定ABS中Pb、Cd、Hg

以ABS塑料为研究对象,采用微波消解法进行样品的前处理,使用电感耦合等离子体发射光谱法测定ABS塑料中Pb、Cd、Hg,结果表明,Pb、Cd、Hg加标回收率均在95~105%之间,测试精密度均小于3%,该方法在缩短样品前处理时间的同时得到较高的元素消解回收率和较为理想的精确度,适用于ABS塑料中重金属含量的快速测定。     

微波消解-电感耦合等离子体质谱(ICP-MS)法同时测定畜禽粪便中7种重金属元素

粪便样品干燥、研磨后,称取0.25 g样品,加入8 mL硝酸,采用微波消解方法进行前处理.采用KED模式消除质谱干扰,采用内标校正消除非质谱干扰(Ge作为Cu、Zn、Cr的内标,Bi作为Hg和Pb的内标,Rh作为As和Cd的内标),建立了可同时测定畜禽粪便中Cu、Zn、Cr、As、Cd、Pb、Hg 7种重金属元素的微波...     

ICP-AES法测定化妆品中铅、镉、砷、汞、锑、铬、镍、钡、锶等禁限用元素含量

建立了化妆品中铅(Pb)、镉(Cd)、砷(As)、汞(Hg)、锑(Sb)、铬(Cr)、镍(Ni)、钡(Ba)、锶(Sr)含量的电感耦合等离子体原子发射光谱法(ICP-AES)同步检测技术。采用微波消解,在较难消化的化妆品中加HF进行消化,铑(Rh)为内标元素消除基体干扰,以配备耐HF进样系统的ICP-AES进行测定。在0～1.0 mg/L范围内呈现良好的线性关系(相关系数≥0.9999),Pb、Cd、As、Hg、Sb、Cr、Ni、Ba、Sr检出限分别为0.0016,0.0007,0.0021,0.0013,0.0003,0.0009,0.0008,0.0009,0.0021 mg/L,方法回收率80.2%～111%,精密度1.7%～8.2%。结果表明,该方法适用于检测基体复杂的化妆品中Pb、Cd、As、Hg、Sb、Cr、Ni、Ba、Sr。     

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。     

原子吸收光谱法测定香烟烟气中重金属的含量

用原子吸收、荧光光谱法测定了不同品种香烟烟气的水吸收液中铅(Pb)、镉(Cd)、铬(Cr)、汞(Hg)的含量,并用等离子体发射光谱法进行比较测定。结果表明,原子吸收光谱法具有灵敏度高、干扰小、快捷的优点。方法回收率为98%～100%,相对标准偏差小于5.0%。实际样品测定结果令人满意。     

微波消解-电感耦合等离子体质谱法测定蔬菜中铬、镉、砷、铅、汞的含量

取经洗净、切成小段并用四分法取样和粉碎的蔬菜样品1.000g于PTFE消解容器中,加入硝酸7mL在消解仪中于120℃恒温保持30min。随后将容器移入微波消解仪中,在1 000 W功率下按设定程序消解25min。冷却后用硝酸(2+98)溶液将消解完全的溶液定容至25.0mL,用电感耦合等离子体质谱法测定样品中Cr、Cd、As、Pb、Hg的含量。对测定中遇到的同量异位素干扰,选取相应的原子丰度较高的同位素~(52)Cr,~(111)Cd,~(75)As,~(208)Pb及~(202)Hg作为被测元素,可在一定程序上降低此类干扰。此外,蔬菜中常含有C、H、O、N、Cl、S、Mo等元素,能与载气中的Ar结合产生多原子离子干扰。因此,在测定~(111)Cd,~(52)Cr,~(75)As时,采用DRC模式并以NH_3作为反应气可消除此类干扰。测定~(202)Hg及~(208)Pb时无此类干扰,故采用STD模式。对样品的基体干扰,采用在线内标加入法予以校正。在DRC模式下测定~(111)Cd,~(52)Cr及~(75)As时可能产生新干扰,采用设定RPq值可排除此类干扰。试验结果表明:所测定的5种元素的质量浓度在一定范围内与各元素的分析信号强度之间呈线性关系,其检出限(3s/k)在0.2～3.2μg·kg~(-1)之间。按标准加入法进行回收试验,测得回收率在92.9%～108%之间,测定值的相对标准偏差(n=5)在1.2%～5.8%之间。     

预还原氢化物发生—原子荧光光谱法快速测定化探样品中的As,Sb,Bi,Hg

通过对化探样品进行王水密闭溶解,饱和的硫脲-抗坏血酸预还原,运用氢化物发生-原子荧光光谱法实现了地质样品中As、Sb、Bi、Hg元素的任意配对以及连续快速测定。实验确定了原子化器高度为14mm,最佳溶样时间为1h。在优化条件下,结果显示还原剂(硫脲-抗坏血酸)对Hg、Bi测定结果无影响,且Hg、Bi测定结果在预还原20min至48h内都很稳定,测定结果良好,Cu、Co、Ni、Au、Ag、Cd、As、Sb、Bi、Se、Ge等金属离子对预还原测定汞均无干扰,对比实验表明还原剂体系下汞荧光强度值基本不变。方法的检出限低、精密度好、准确度高、操作简便,有效避免了元素污染问题,可满足大批量地质样品分析测定的需要。     

Development of an accurate,sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine,sulfur, and heavy metals) in coal samples

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for ³⁵Cl⁺ to more than 6 × 10⁵ cps for ²³⁸U⁺ for 1 μg of trace element per gram of coal sample. Detection limits vary from 450 ng g⁻¹ for chlorine and 18 ng g⁻¹ for sulfur to 9.5 pg g⁻¹ for mercury and 0.3 pg g⁻¹ for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis. Figure LA-ICP-IDMS allows direct multi-element determination in powdered coal samples     

Effect of Anions on the Development of Color Reactions of Cadmium, Lead, and Mercury with Dithizone and 4-(2-Pyridylazo)resorcinol on a Fibrous Material Filled with the Anion Exchanger AV-17

The effect of nitrates, chlorides, iodides, sulfates, thiosulfates, thiocyanates, acetates, tartrates, nitrilotriacetates, and ethylenediaminetetraacetates in the sorption of Cd(II), Pb(II), and Hg(II) and their subsequent determination with dithizone and 4-(2-pyridylazo)resorcinol (PAR) on the solid phase of a fibrous anion-exchange sorbent filled with AV-17 was studied. The dependences of the analytical signals of complexes adsorbed on the solid phase on the concentration of anions in the solution and on the stability of anionic complexes were revealed. The analytical signals in the sorption and determination of Cd, Pb, and Hg with dithizone and PAR on the solid phase were maximum for iodide and thiosulfate complexes. Conditions of the sorption of Cd(II), Pb(II), and Hg(II) were found for their subsequent total and separate determination with PAR and dithizone.     

Determination of As,Cd, Cr,Cu, Hg,Sb and Se concentrations by radiochemical neutron activation analysis in different Brazilian regional diets

The present paper describes radiochemical separation procedures developed for the determination of seven elements: As, Cd, Cr, Cu, Hg, Sb and Se in different Brazilian regional diets. In the case of the elements As, Hg, Sb and Se, the procedure was based on retention in inorganic exchanger TDO (tin dioxide) and determination of Hg by extraction with Ni(DDC)₂. For determination of Cd, Cr, Cu and Se the procedure chosen was based on retention in inorganic exchanger HMD (hydrated managese dioxide) and extraction of Cu and Cd as diethyldithiocarbamate compounds. The accuracy and precision of the methods studied were tested by means of analyses of different reference materials. Due to the lack of data on trace element levels in Brazilian foodstuffs and diets, these methods were applied to determination of these elements in different Brazilian regional diets. These diets were supplied by the Food and Experimental Nutrition Department of the Faculty of Pharmaceutical Science, University of São Paulo. The daily dietary intake values for these diets are presented for As, Cd, Cr, Cu, Hg, Sb and Se.     

Determination of Hg(II) in Environmental Water Samples by Dispersive Liquid Phase Microextraction Combined with Flame Atomic Absorption Spectrometry

In this study, a method of dispersive liquid phase microextraction combined with the flame atomic absorption spectrometry was proposed for the determination of trace Hg using diphenylthiocarbazone as chelating reagent. Several factors which have effect on the microextraction efficiency of Hg, such as pH, extraction and dispersive solvent type and their volume, concentration of the chelating agent, extraction time were investigated, and the optimized experimental conditions were established. After extraction, the enrichment factor was 68. The detection limit of the method was 45 ng mL^?1, and the relative standard deviation for eight determinations of 2 μg mL^?1 Hg was 1.7%. The results for the determination of Hg in environmental water samples (tap water, well water, mineral water and Caspian sea water) have demonstrated the applicability of the proposed method.     

Kinetic determination of Hg(II) in different materials, based on its inhibitory effect on a catalysed process

A new kinetic method for the determination of Hg(II) based on its inhibitory effect on the Pd(II)-catalysed reaction between Co(III)-EDTA and hypophosphite is proposed. The reaction is followed spectrophotometrically at 540 nm by measuring the induction period. Both the influence of the reaction variables and the interference of many ions have been studied. A mechanism for the inhibition process is also proposed. Under the selected experimental conditions of 2.7 x 10(-1)M Co(III)-EDTA, pH-3.2 Britton-Robinson buffer, 0.3M H(2)PO(-)(2), 0.35 mug/ml Pd(II), and temperature 18 +/- 0.2 degrees , Hg(II) was determined in the range 13-120 ng/ml. The method was applied to the determination of Hg(II) in sphalerites and pharmaceuticals.     

Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge,As, Cd,Sb, Hg and Bi in cosmetic lotions

A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v l-cysteine, 0.5 μg mL⁻¹ Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng  g⁻¹ for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.     

Highly sensitive, selective, and rapid fluorescence Hg2+ sensor based on DNA duplexes of poly(dT) and graphene oxide

Coupling T base with Hg(2+) to form stable T-Hg(2+)-T complexes represents a new direction in detection of Hg(2+). Here a graphene oxide (GO)-based fluorescence Hg(2+) analysis using DNA duplexes of poly(dT) that allows rapid, sensitive, and selective detection is first reported. The Hg(2+)-induced T(15)-(Hg(2+))(n)-T(15) duplexes make T(15) unable to hybridize with its complementary A(15) labelled with 6'-carboxyfluorescein (FAM-A(15)), which has low fluorescence in the presence of GO. On the contrary, when T(15) hybridizes with FAM-A(15) to form double-stranded DNA because of the absence of Hg(2+), the fluorescence largely remains in the presence of GO. A linear range from 10 nM to 2.0 μM (R(2) = 0.9963) and a detection limit of 0.5 nM for Hg(2+) were obtained under optimal experimental conditions. Other metal ions, such as Al(3+), Ag(+), Ca(2+), Ba(2+), Mg(2+), Zn(2+), Mn(2+), Co(2+), Pb(2+), Ni(2+), Cu(2+), Cd(2+), Cr(3+), Fe(2+), and Fe(3+), had no significant effect on Hg(2+) detection. Moreover, the sensing system was used for the determination of Hg(2+) in river water samples with satisfactory results.     

Kinetic determination of Hg(II) based on its accelerating effect on the reaction between hexacyanoferrate(II) and 1,10-phenanthroline catalysed by micelles

A kinetic-photometric method for the determination of Hg(II) over the range 10-80 ng/ml is proposed. It is based on the accelerating effect of this ion on the reaction between hexacyanoferrate(II) and 1,10-phenanthroline which is monitored via the ferroin complex formed. Anionic sodium dodecyl sulphate (SDS) micelles, which catalyse the reaction, allow the ferroin complex to be formed under more acidic conditions. Combination of this pH shift and the development of the reaction in the vicinity of micelles results in improved selectivity in the determination of Hg(II) compared to the reaction occurring in an aqueous medium. Some observations on the effect of SDS on the reaction are reported.     

Square wave voltammetric determination of Hg(II) using thiol functionalized chitosan-multiwalled carbon nanotubes nanocomposite film electrode

Covalent tethering of cysteamine to chitosan using glutaraldehyde yields thiol-functionalized chitosan (CS-SH). It was cast on a glassy carbon electrode which is found to be very stable in acidic solutions and to possess a strong affinity for Hg(II) ions as confirmed by quartz crystal microbalance measurements. A glassy carbon electrode modified with a nanocomposite made from CS-SH and multiwalled carbon nanotubes was applied for square wave voltammetric determination of Hg(II). The procedure comprises the steps of (a) chemical accumulation of Hg(II) under open-circuit condition and (b) electrochemical determination of Hg(II). Linear responses are obtained in the range from 10 to 140 nM, with a limit of detection of 3 nM (S/N?=?3) under optimized conditions. The electrode was applied to the determination of Hg(II) in water samples with satisfactory recoveries.