Simultaneous determination of some trace metal impurities in high-purity sodium tungstate using coprecipitation and inductively coupled plasma atomic emission spectrometry

A method based on the combination of coprecipitation with inductively coupledplasma atomic emission spectrometry (ICP-AES) was developed for the determination of impurities inhigh-purity sodium tungstate. Six elements (Co, Cu, Fe, Mn, Ni, and Pb) were coprecipitated bylanthanum hydroxide so as to be concentrated and separated from the tungsten matrix. Effects of somefactors on the recoveries of the analytes and on the residual amount of sodium tungstate wereinvestigated, and the optimum conditions for the coprecipitation were proposed. Matrix-matchingcalibration curve method was used for the analysis. It is shown that the elements mentioned abovecan be quantitatively recovered. The detection limits for Co, Cu, Fe, Mn, Ni, and Pb are 0.07, 0.4,0.2, 0.1, 0.6, and 1.3 μg·g^(-1), respectively. The recoveries vary from 92.5% to 108%, and therelative standard deviations (RSDs) are in the range of 3.1%-5.5%.

Reagent optimization for on-line simultaneous polarographic determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of anextremely large excess of Zn^(2+)

Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).

Determination of Some Heavy-metal-ions Using a Sulfur Ion Modified BZ Oscillating System

A highly sensitive method is developed for the determination of trace amounts of some heavy metal ions in aqueous solution based on the classical Belousov-Zhabotinskii （BZ） oscillating chemical system. Introducing of S^2- ion makes the new oscillating system Ce（SO4）2 - KBrO3 - CH2（COOH）2 - Na2S - H2SO4 have to a high sensitivity for some heavy metal ions such as Ag^＋, Pb^2＋, Hg^2＋, Cd^2＋, Cu^2＋and Bi^3＋ with detection limits down to 10^-12 mol·L^- 1

Determination of Kinetic Parameters and Metal Ions in Urea-Urease System Based on the Biochemical Reaction Heat Induced Laser Beam Deflection

A new analytical method for the determination of urea-urease system based on biochemical reaction heat induced laser beam deflection is presented in this paper. With the method, the Michaelis constant (K-m) of urease and apparent inhibition constant (K-i) of some metal ion inhibitors were measured respectively. This method was also used for the quantitative determination of metal ions with satisfactory result.

Detection of Trace Heavy Metals Ions by Arrays of Titania Nanotubes Annealed in Nitrogen

Redox response of trace heavy metals ions（THMIs） has better performance on highly ordered vertically oriented titania nanotube arrays（TNA） annealed in nitrogen. Experimental data showed that different THMIs possess different reaction peak shapes and charge and discharge capacities. Therefore, the TNA will become an important tool used for environmental protection and facilitating the rapid determination of THMIs. THMIs of 5×10^4 mol/L concentration were measured at a scan rate of 100 mV/s. The analytical utility of TNA is demonstrated in a neutral 0.5 mol/L Na2SO4 solution. The results sufficiently show that titania nanotube arrays electrodes（TNAE） will be used to measure THMIs.

Solid-liquid solvent extraction of metal ions

An overview of extraction of some trace metal ions using molten solvent (lowmelting substance) during last two decades is presented. The development of this technique since itsinception is briefly traced. The comparison of extraction efficiency, thermodynamics and kineticsmainly involving extraction of rare earth ions between molten solvent extraction at high temperatureand usual liquid-liquid extraction at room temperature are discussed in detail. The variousparameters obtained from the previous and present studies such as equilibrium extraction constantK_(ex), pH_(1/2), thermodynamic and kinetic data are displayed in tabular form. Finally, the currentdemands, disadvantages and future prospects are also evaluated.

Analysis of trace elements in air particulate matters by non-suppressed ion chromatography

The application of non-suppressed ion chromatography for monitoring of trace elements in air particulate matter was studied in the present investigation. The results indicate that the use of microwave acid digestion method is superior in comparison with the conventional thermal acid digestion method as it leads to higher recovery, better reproducibility, lower volatility loss, better protection against environmental contamination and much less digestion time (5 minutes vs. 24 hours). The use of eluent as extractant is shown to reduce the water dip problem in the chro-matogram. The addition of chelating agent in the eluent coupled with UV detection is shown to provide satisfactory chromatographic separation and good sensitivity for the analysis of transition metals present in the air particulate matter. Using the U.S. National Bureau of Standards Reference Material 1648 Urban Particulate Matter as standard for checking, the analytical procedure is shown to give good recovery and reproducibility for the detection of the following cations and anions in air particulate matter: Fe2 Cu, Mn, Pb, Zn, Mg, Na, HN4+, Cl-, NO3- and SO42-. Field test was also performed to check the applicability of the method and the results obtained were discussed in the present paper.

Chemical Composition and Source Characterization of Hailstones in Dhaka, Bangladesh

A comprehensive analysis on the chemical composition and source apportionment of hailstone samples were conducted in Dhaka, Bangladesh. pH, electrical conductivity (EC), total dissolved solids (TDS), water soluble ions (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, NO3-, HCO3-) and trace metals (Zn, Fe, Cu, Mn) of hailstone were determined. The result revealed that the average pH, EC, TDS were 6.95 ± 0.54, 356.3 ± 150.6 μS·cm-1 and 17.5 ± 2.89 mg·L-1, respectively. The water soluble ions followed the order: Ca2+ > Cl-1 > SO42- > HCO3- > Na+ > Mg2+ > K+ > NO3-. The concentrations of trace metals ranged in order with Zn > Fe > Cu, while the concentration of Mn was below detection limit. Sodium adsorption ratio (SAR) was 0.20 ± 0.09 meqL-1 which indicates it is benign to plants and safe for irrigation. The order of neutralization factor (calculated with average concentrations) found in hailstone was NFCa(1.16) > NFMg (0.36) > NFK(0.32) which were originated from earth crust. Notable correlation was found in between soil tracers Ca2+ and Mg2+ (r = 0.87), indicating their common source dust. Enrichment factor analysis revealed that Ca2+, Mg2+ and K+ are mainly from crust, whereas NO3- and SO42- are mainly attributable to anthropogenic origins. Further source contribution analysis revealed that anthropogenic actions accounted for 99.2% of total NO3- and 89.6% of total SO42-, while 99.2% of total Ca2+ and 95% Mg2+ were from crustal source.

Elemental Quantification in Intradermal Tattoo-Inks by Means of Total Reflection X-Ray Fluorescence

This work describes the application of a detailed set of TXRF evaluations to the elemental content of assorted tattoo inks, on the market of the city of Concepcion, Chile. We applied TXRF as a screening method for determining the composition in 3 sets of tattoo inks, in order to establish, from an inorganic point of view, the composition and purity of the samples, evaluating their elemental innocuousness. The analyzed 48 products were freely acquired from on line suppliers. All of them were analyzed by external standard quantification, but in order to inter-compare the results, a 15% of the samples were acidly digested and then quantified by the internal standard method. In the samples we determined: 1) their inorganic quantitative composition and, 2) the possible presence of elements which are potential health hazards. In this study few anomalies were found: 1) The high presence Ti of and W in few samples, 2) Arsenic was found in four of them, and 3) A trace detection of a rare earth element in a particular product. The products studied are almost freely imported from a world open marked, so the questions about their innocuousness could affect not only to the Chilean society.

纳米复合材料吸附剂用于水中痕量金属的测定

为实现地质勘查水体中痕量金属元素的同时检测,建立基于氧化石墨烯/氧化多壁碳纳米管(GO/MWCNTs)吸附剂的分散固相微萃取程序同时测定水中痕量金属的方法,并对方法的检测性能进行研究。结果表明,用GO与MWCNTs比例为1∶5制备的GO/MWCNTs复合材料作为吸附剂,水样pH值为8、水样体积为60 mL,搅拌时间为5 min的条件下进行分散固相微萃取,此时对水中痕量重金属吸附回收率超过95%;通过XRF对萃取后的材料进行检测,金属元素在荧光图谱中显示的较为明显,且谱线间相互不干扰。

Seasonal variations in aerosol compositions at Great Wall Station in Antarctica

High volume aerosol samplers at Great Wall Station in Antarctica were used to collect 73 aerosol samples between January 2012 and November 2013. The main ions in these aerosol samples, Cl^-, NO3-, SO4^2-, Na＋, K＋, Ca2＋, Mg2＋, NH4＋, as well as methane sulfonic acid, were analyzed using ion chromatography. Trace metals in these samples, including Pb, Cu, Cd, V, Zn, Fe, and Al, were determined by inductively-coupled plasma mass spectrometry. Results showed that sea salt was the main component in aerosols at Great Wall Station. Most ions exhibited significant seasonal variations, with higher concentrations in summer and autumn than in winter and spring. Variations in ions and trace metals were related to several processes（or sources）, including sea salt emission, secondary aerosol formation, and anthropogenic pollution from both local and distant sources. The sources of ions and trace metals were identified using enrichment factor, correlation, and factor analyses. Clearly, Na＋, K＋, Ca2＋, and Mg2＋were from marine sources, while Cu, Pb, Zn, and Cd were from anthropogenic pollution, and Al and V were mainly from crustal sources.

ICP-MS/MS直接测定海水中12种痕量金属元素

建立一种采用电感耦合等离子体串联质谱(ICP-MS/MS)直接测定海水中12种元素的分析方法。采用标准加入法及配置超高基体进样系统实现基体匹配,应用ICP-MS/MS的多种分析模式测定海水中钒(V)、铬(Cr)、锰(Mn)、钴(Co)、镍(Ni)、铜(Cu)、锌(Zn)、砷(As)、钼(Mo)、镉(Cd)、铊(Tl)、铅(Pb)12种痕量元素。用该方法测定海水标准参考物质,结果准确。测定实际海水样品,加标回收率为85.0%~108%,相对标准偏差为1.5%~5.4%。12种元素的方法检出限为0.003~0.085μg/L,定量下限为0.012~0.340μg/L。该方法运行成本低,操作便捷,可作为实验室海水元素分析的常规检测方法。

金属离子掺杂羟基磷灰石骨修复材料的特性及应用

背景:目前用于骨修复的自体骨和异体骨存在来源有限、供骨区并发症、潜在的疾病传播风险、免疫排斥反应及价格昂贵等问题,临床应用受到限制,人工骨修复材料作为骨移植替代材料得到了广泛研究。目的:总结金属离子掺杂改性羟基磷灰石用于骨组织修复的研究现状。方法:检索2000年1月至2022年5月PubMed、Web of Science、中国知网及万方数据库收录的相关文献,中文检索词为“金属离子、羟基磷灰石、掺杂改性、骨修复”,英文检索词为“Metal ion,Hydroxyapatite,Doping modification,Bone repair”。最终纳入61篇文献进行综述分析。结果与结论:①离子掺杂羟基磷灰石具有良好的特性,锶可增强成骨细胞的骨生成过程,并抑制破骨细胞介导的骨吸收,锶掺杂羟基磷灰石在骨质疏松性骨缺损修复方面具有独特的优势。②铜、锌、银、镁、铁具有一定的抗菌活性,其中银、锌具有优异的抗菌性,掺杂改性羟基磷灰石对预防和治疗骨科感染具有重要意义。③铜可促进血管内皮细胞迁移,增加血管生成,掺铜羟基磷灰石可用于乏血管部位的骨组织修复。钡具有显影性,与羟基磷灰石等其他材料复合可制备显影骨修复材料。④锶-铁共掺杂羟基磷灰石可调节细胞免疫,促进血管和骨生成。镁、锌-锶掺杂的羟基磷灰石可诱导利于成骨的弱碱性环境,具有优异的成骨能力。⑤一定含量的镁掺杂的羟基磷灰石具有与皮质骨相匹配的抗压强度,有望用于负重部位的骨组织修复。低浓度的离子掺杂可提高羟基磷灰石的机械性能和成骨活性,并赋予其抗菌活性、促血管生成、免疫调节等能力。⑥当离子浓度过高时,则会产生毒性作用,目前关于各离子的最佳掺杂浓度尚无定论,未来需深入研究。⑦离子参与骨代谢的机制以及是否会影响其他细胞活动需关注探索;如何实现植入材料的缓慢降解、金属离子的缓慢释放,使其与骨修复过程相匹配,有待进一步研究。⑧优化羟基磷灰石的合成方法和离子掺杂技术,制备与天然骨机械性能匹配的材料是今后研究的一个方向。

超级微波消解-电感耦合等离子体发射光谱(ICP-OES)法测定锂离子电池隔膜中8种痕量金属元素

锂离子电池隔膜直接影响锂离子电池的安全性能和整体性能,是锂离子电池十分重要的组成部分,通过考察最佳消解前预加热处理温度及时间、超级微波消解体系、超级微波消解时间及温度、分析谱线,建立了超级微波消解-电感耦合等离子体发射光谱(ICP-OES)法测定锂离子电池隔膜中铁、铜、锌、铬、铝、钠、钙、镁元素的方法。结果表明,4 mL硝酸-1 mL高氯酸-3 mL磷酸消解体系在电热板上120℃预加热1 h后,再在260℃的超级微波中消解40 min的消解效果最好,ICP-OES测定结果表明各元素在质量浓度为0~5 mg/kg范围内标准曲线的线性关系良好,相关系数为0.99993~0.99999,测试结果精密度为0.30%~2.8%,加标实验回收率为91.4%~99.9%。方法准确且简便,能实现对锂离子电池隔膜中痕量金属元素含量的高通量及快速测定,为评价锂离子电池隔膜中痕量金属元素含量提供科学的数据参考。

食品中重金属元素痕量分析消解技术的进展与应用

食品中重金属元素痕量分析消解技术是分析过程中最关键的步骤,直接关系到分析方法的优劣。本文概述了干灰化、湿式消解、微波消解和高压罐消解4种方法的原理和特点;根据重金属元素特性,探讨了的各种消解方法的适用范围、应用情况、最新进展及其对不同元素和检测仪器的适用性。本文表明:1.控制消解过程的污染,降低样品空白值是重金属痕量分析质量控制的关键点;2.高压罐消解法和微波消解法的样品空白值低于湿式消解法和干灰化法;3.应根据元素特性、检测目的以及样品空白值大小选择合适的前处理消解方法:食品中汞的测定宜采用高压罐消解或微波消解法,食品中砷的测定最好采用湿式消解法,食品中铅、镉、铜、镍、铝和硼的质量控制考核或本底值测定可采用高压罐消解和微波消解,而日常检测或半定量测定可采用湿式消解。

低压离子色谱分离-化学发光在线检测过渡金属离子

研究了低压离子色谱 (LPIC)分离 柱后鲁米诺化学发光 (CL)检测方法 ,并分离测定了Cu2 + ,Co2 + ,Cr3 + ,Fe2 + ,Mn2 + 等 5种过渡金属离子。以草酸 柠檬酸混合溶液作为洗脱液 ,Luminol H2 O2 Mn + 作为化学发光检测体系 ,对过渡金属离子进行在线检测。测定的线性范围分别为 (mg·L-1) :Co2 + ,0 0 0 1～ 0 .1;Cu2 + ,0 1～ 6 ;Mn2 + ,0 0 6～ 4 ;Fe2 + ,0 0 3～ 5 ;Cr3 + ,0 0 2 5～ 1。检测限分别为 (μg·L-1) :Co2 + ,0 85 ;Cu2 + ,85 ;Mn2 + ,4 2 ;Fe2 + ,2 1;Cr3 + ,2 0。利用此法测定了维生素B12 中Co2 + 以及人发样中Cu2 + ,Mn2 + ,Cr3 + ,Co2 + 和Fe2 + 等离子的含量 ,结果与原子吸收法所测值基本吻合。

藻类对痕量金属元素的吸收研究

近年来,由于传统的清除水体中重金属污染的方法效率低且成本太高,以藻类为主要材料来清除水体中的重金属已逐渐成为研究热点。海藻在海水中的含量比较丰富,并且用海藻来吸收重金属有很好的环境效益。对藻类与重金属的相互作用机理,以及藻类吸收重金属在测定海水中重金属含量时的意义进行了总结。对藻类在吸收重金属时的几个影响因素,如藻的种类、培养基上的金属浓度、金属的种类、温度以及pH值也进行了论述。

变色酸2C和TAN双显色体系RP-HPLC法分离测定铍(Ⅱ)、铬(Ⅲ)、铜(Ⅱ)、铁(Ⅱ)、镍(Ⅱ)

基于变色酸 2 C和 TAN双显色体系发展了一种同时测定铍 ( )、铬 ( )、铜 ( )、铁 ( )和镍 ( )的新 RP-HPLC法 .在 p H=5 .0的乙酸盐缓冲介质中 ,同时加入变色酸单偶氮试剂变色酸 2 C和噻唑偶氮试剂TAN,它们能与不同金属离子形成有色螯合物 ,以 YWG-ODS柱为固定相 ,含显色剂、溴化四丁铵和乙酸盐缓冲溶液 ( p H=5 .0 )的甲醇 /乙醇 /水 (体积比 35 :5 :60 )溶液为流动相 ,并用分光光度检测器于 5 80 nm处测量 ,用 RP-HPLC可成功地分离和测定 ng/ m L级的铍 ( )、铬 ( )、铜 ( )、铁 ( )和镍 ( )等 5种金属离子 .此方法灵敏度高 ,简便快速 ,用于大米、面粉中上述金属离子的测定 。