光谱载体氯化锂对ICP-OES法测定铅锰的影响

为研究光谱载体LiCl对ICP-OES法测定Pb、Mn的影响,通过测定在不同LiCl浓度、射频功率、观测高度、载气流量和进样量条件下谱线Mn Ⅰ 279.482nm,Mn Ⅰ 403.075nm,Mn Ⅱ 257.610nm,Mn Ⅱ 259.372nm,Pb Ⅰ 217.000nm,Pb Ⅰ 283.306nm,Pb Ⅱ 220.353nm的净强度,得到了各谱线灵敏度的影响规律。证明LiCl是ICP-OES法测定Pb、Mn的良好光谱载体,LiCl增敏ICP-OES法测定地表水中Pb、Mn是可行的。     

原子吸收法测定白酒中铅和锰的方法改进

目的:本文以简化操作步骤,改进实验方法为目的,着重研究利用原子吸收光谱法直接测定白酒中的铅和锰。方法:直接对样品进行稀释,用火焰原子吸收法测定锰。以磷酸氢二铵为基体改进剂,用石墨炉原子吸收光谱法测定铅。结果:该方法操作简单快速,减少了试剂用量,而且精密度和准确度都能满足实验要求。结论:该方法是可行的,值得推广使用。     

ICP-OES法测定焊锡中铅铜银等多种元素

本文用电感耦合等离子发射光谱法(ICP-AES)同时测定测焊锡中的多种金属元素,用硝酸-氢氟酸混酸溶解样品,加入硫脲稳定溶液中的银离子。以基体匹配法配制工作曲线标样,有效地消除了基体干扰。方法简便、可靠,能满足焊锡样品测定的要求。     

微波消解-电感耦合等离子体原子发射光谱仪（ICP—OES）测定玩具涂层中的铅元素

采用不同的微波消解温度和不同混合酸消解油漆粉末标准参考物（NISTSRM2582）,用ICP—OES测定铅元素的含量。依据精密度、回收率,比较了消解温度、混合酸对NISTSRM2582的消解效果。结果表明,由60mL浓硝酸和180mL浓盐酸混合后稀释到1000mL后组成的混合酸对玩具涂层具有很好的消解能力,微波加热15min能迅速有效消玩具涂层,铅元素的测定值与标称值非常符合。     

火焰原子吸收光谱法测定压力容器用钢板中锰含量

目的:建立测定压力容器用钢板中锰含量的火焰原子吸收光谱法,并用该方法测定5批不同规格的钢板。方法:检测波长279.5nm,狭缝宽度0.2nm,灯电流20mA,空气流量17.0L·min-1,乙炔气流量2.0L·min-1。结果:锰浓度在2.0-30.0μg·mL-(1r=0.9997)范围内线性关系良好,平均加样回收率(n=6)为98.4%(RSD=2.3%)。结论:该法是一种快速、灵敏、准确的分析方法,可以为压力容器用钢板的质量控制提供科学依据。     

一种全新的原子吸收光谱法测定钢铁中锰含量的探讨

由于锰在钢铁中起着不可低估的作用,而钢铁的品种不同,锰元素的含量也有很大差异。本文主要介绍了一种用硫硝混酸溶解钢铁样品,然后用火焰原子吸收光谱法以系列标钢样品绘制标准曲线来测定其锰含量的新方法。     

原子吸收光谱法测定水中铅的不确定度分析

目的:为提高检测结果精确度,评定水中铅的不确定度。方法:分析水中铅不确定度的来源,通过计算得出该法测定水中铅的扩展不确定度。结果:测量结果表明扩展不确定度U95=2.3μg/L,适用于每个水样的检测结果。结论:该方法简便,适合于每一个样本的检测结果,可参考用于水中某些检测参数的不确定评定。     

原子吸收光谱法测定汽油中锰含量不确定度的评定

通过分析原子吸收法测定汽油中锰含量操作过程,对锰含量测定结果的不确定度进行了评定。不确定度主要来源于样品溶液浓度和重复性,样品溶液浓度影响中尤以标准曲线拟合对不确定度的贡献最大。当汽油锰含量为4.89mg/L时,其扩展不确定度为1.18mg/L(k=2)。     

原子吸收法测定酱油中铅不确定度的评定

通过对测定酱油中铅含量的不确定度评定分析,找出不确定度产生的主要因素,评定确认最小二乘法拟合校准标准曲线及测量重复性是影响结果的最主要因素,使用标准物质(标准储备液)及稀释过程引入的不确定度也应引起重视,此方法对类似的火焰原子吸收法测定样品中待测元素含量有借鉴和参考作用。     

乙炔-空气火焰原子吸收光谱法测定地质样品中的锰

采用了乙炔-空气火焰原子吸收光谱法测定地质样品中的锰。在仪器最佳工作条件下,具有较高的灵敏度,而且还能消除多种共存元素的干扰。乙炔-空气火焰原子吸收光谱法已经越来越普遍的被应用于检测地质中的化学元素。这种方法发展的十分迅速。     

ICP-OES法测定硅锰、锰铁合金中磷含量

应用ICP—OES法测定硅锰、锰铁合金中磷的含量,对试样前处理及分析方法的各种参数进行了优化,包括溶样酸的选择,分析谱线的选择,试样基体、分析酸度和干扰元素对测定结果的影响。通过各种分析参数的优化选择实现了硅锰、锰铁中磷的测定,取得了满意的效果。线性相关系数：P=0．9998,检测限为：0．030％。该分析方法准确快速,试剂用量少,线性范围宽,适用于硅锰、锰铁合金中质量分数为0．03～0．50％的磷测定。     

ICP-OES法测定烟道灰中的镓和锗

研究了ICP-OES法同时测定烟道灰中的镓和锗。试验确定了以(HF+HClO4)溶解样品,讨论了分析谱线的选择,干扰及其校正。试验对仪器的功率和工作气体流量等条件进行了优化,建立了分析方法。结果表明,两种元素的回收率为97%~103%,相对标准偏差为0.79%~2.45%,方法简便、快速、易行,完全满足分析的需要。     

Zincon-modified activated carbon for solid-phase extraction and preconcentration of trace lead and chromium from environmental samples

A new method that utilizes zincon-modified activated carbon (AC-ZCN) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III) and Pb(II) onto the AC-ZCN were 17.9 and 26.7 mg g⁻¹, respectively. The adsorbed metal ions were quantitatively eluted by 1 mL of 0.1 mol L⁻¹ HCl. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3σ) of this method for Cr(III) and Pb(II) were 0.91 and 0.65 ng mL⁻¹, respectively. The relative standard deviation under optimum condition is less than 3.5% (n = 8). The method has been applied for the determination of Cr(III) and Pb(II) in biological materials and water samples with satisfactory results.     

The effects of point of substitution on the formation of manganese phthalocyanine-based molecular materials: Surface characterization and electrocatalysis

Molecular films of manganese phthalocyanine (MnPc) complexes, tetra-substituted with 2-diethylaminoethanethio at the peripheral (Mn(OAc)-β-TDEAETPc, 1) and non-peripheral (Mn(OAc)-α-TDEAETPc, 2) positions were formed on glassy carbon electrode by electropolymerization and electrodeposition respectively. Atomic force microscopy images confirmed the presence of the films and revealed significant morphological differences. The films exhibited an electrocatalytic activity towards the oxidation of the insecticide, bendiocarb. Hydrodynamic technique, using rotating disc electrode voltammetry, was used to investigate the kinetics of electro-oxidation of the insecticide. Morphological differences of the films significantly influenced kinetic parameters. Values of Tafel slopes, obtained from Tafel plots, suggested that catalysis of bendiocarb occurred via outer sphere mechanism.     

Atomic layer deposition of MnO using Bis(ethylcyclopentadienyl)manganese and H2O

Manganese oxide (MnO) atomic layer deposition (ALD) was accomplished using sequential exposures of bis(ethylcyclopentadienyl)manganese (Mn(CpEt)₂) and H₂O. Rutherford backscattering analysis revealed a nearly 1:1 atomic ratio for Mn:O in the MnO ALD films. X-ray diffraction determined that the films were crystalline and consistent with the cubic phase of MnO. Quartz crystal microbalance (QCM) measurements monitored the mass deposition rate during MnO ALD and verified self-limiting reactions for each reactant. Extremely efficient reactions were observed that required reactant exposures of only 3 × 10⁴ L (1 L = 1.33 × 10^− 4 Pa s). X-ray reflectivity (XRR) studies were used to confirm the QCM measurements and determine the film density and film thicknesses. The MnO ALD film density was 5.23 g/cm³. The growth per cycle was investigated from 100-300 °C. The largest MnO ALD growth per cycle was 1.2 Å/cycle at 100 °C and the growth per cycle decreased at higher temperatures. Transmission electron microscopy images observed the conformality of MnO films on ZrO₂ nanoparticles and confirmed the growth per cycle observed by the XRR studies. Fourier transform infrared spectroscopy was used to study the -CpEt? and -OH? surface species during MnO ALD and also monitored the bulk vibrational modes of the growing MnO films. The results allowed a growth mechanism to be established for MnO ALD using Mn(CpEt)₂ and H₂O. Only 54% of the Mn sites are observed to retain the -CpEt? surface species after the Mn(CpEt)₂ exposure. Efficient MnO ALD using Mn(CpEt)₂ and H₂O should be useful for a variety of applications where metal oxides are required that can easily change their oxidation states.     

Selective elimination of lead(II) ions by alginate/polyurethane composite foams

A new type of adsorbent which is capable of selectively adsorbing lead(II) ions (Pb(2+)) was developed. The adsorbent was generated by reaction of sodium alginate with NB-9000B, a polyisocyanate type of prepolymer of polyurethane. The adsorbent was a hydrophilic and flexible alginate/polyurethane composite foam (ALG/PUCF) with the alginate chemically immobilized in the cell walls of the foam. Acid-base titration was used to quantify the concentration of carboxyl groups, which are present on the alginate molecules of the ALG/PUCF, functioning as the essential sites for binding Pb(2+). For the optimized ALG/PUCF, the carboxyl was found to be 38.2+/-1.2mumol/g of dry weight. The capacity for adsorbing Pb(2+) ions in 1.0g of dry weight of the optimized ALG/PUCF was found to be 16.0+/-2.1mumol, indicating that ion exchange was the essential mechanism for adsorbing Pb(2+) ions. The adsorption capacity was found to be highly sensitive to the pH of the sample solution; lower pH (<3) significantly decreased the adsorption. Competing ions such as Mg(2+), Ca(2+), and Cd(2+) also caused a decrease in selectivity and capacity for Pb(2+) adsorption, although the effect was less pronounced than the effect of pH. The ALG/PUCF is highly stable, flexible and easy to use. ALG/PUCF is also reusable after regeneration with ethylenediamine-N,N,N',N'-tetraacetic acid, disodium salt (EDTA-2Na). Due to these features, this adsorbent may be highly useful for elimination of Pb(2+) ions from contaminated water.     

Determination of heavy metals by ICP-OES and F-AAS after preconcentration with 2,2'-bipyridyl and erythrosine

The applicability of 2,2'-bipyridyl and erythrosine co-precipitation method for the separation and preconcentration of some heavy metals, such as Cd, Co, Cu, Ni, Pb and Zn in actual samples for their determination by ICP-OES and F-AAS was studied. Experimental conditions influencing the recovery of the investigated metals, such as pH, molar ratio of 2,2'-bipyridyl to erythrosine, the effect of time on co-precipitation were optimized. The analytical characteristics of the method (e.g. limit of detection, sensitivity, linear range and preconcentration factor) were obtained. The limits of detection LOD (ng mL(-1)) of the ICP-OES (F-AAS) method were: Cd: 4.0 (7.75), Co: 3.1 (57.2), Cu: 18 (10.3), Ni 21.3 (32.8), Pb: 35.9 (29.2) and Zn: 10.2 (6.90). The recovery of all the elements tested was more than 93%. The influence of inorganic matrix was examined. The proposed method was applied to determination of Cd, Co, Cu, Ni, Pb and Zn in vegetables and certified reference material (NCS ZC85006 Tomato).     

Removal of aqueous lead ions by hydroxyapatites: equilibria and kinetic processes

The capacity of hydroxyapatite (HAp) to remove lead from aqueous solution was investigated under different conditions, namely initial metal ion concentration and reaction time. The sorption of lead from solutions containing initial concentrations from 0 to 8000 mg/L was studied for three different HAp powders. Soluble Pb and Ca monitoring during the experiment allows characterizing the mechanism of lead uptake. Dissolution of calcium is followed by the formation of a solid solution, Pb(x)Ca(10-x)(PO4)6(OH)2, with a Ca/P ratio decreasing continuously. Langmuir-Freundlich classical adsorption isotherms modeled adsorption data. The adsorption capacities calculated from this equation vary from 330 to 450 mg Pb/g HAp for the different solids. Modeling of the sorption process allows to determine theoretical saturation times and residual lead concentrations at equilibrium.     

Removal of copper(II) and lead(II) from aqueous solution by manganese oxide coated sand I. Characterization and kinetic study

The preparation, characterization, and sorption properties for Cu(II) and Pb(II) of manganese oxide coated sand (MOCS) were investigated. A scanning electron microscope (SEM), X-ray diffraction spectrum (XRD) and BET analyses were used to observe the surface properties of the coated layer. An energy dispersive analysis of X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) were used for characterizing metal adsorption sites on the surface of MOCS. The quantity of manganese on MOCS was determined by means of acid digestion analysis. The adsorption experiments were carried out as a function of solution pH, adsorbent dose, ionic strength, contact time and temperature. Binding of Cu(II) and Pb(II) ions with MOCS was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Cu(II) and Pb(II) adsorption by MOCS, the pH in solution was decreased. Cu(II) and Pb(II) uptake were found to increase with the temperature. Further, the removal efficiency of Cu(II) and Pb(II) increased with increasing adsorbent dose and decreased with ionic strength. The pseudo-first-order kinetic model, pseudo-second-order kinetic model, intraparticle diffusion model and Elovich equation model were used to describe the kinetic data and the data constants were evaluated. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Cu(II) and Pb(II) onto MOCS, suggesting that the adsorption mechanism might be a chemisorption process. The activation energy of adsorption (E(a)) was determined as Cu(II) 4.98 kJ mol(-1) and Pb(II) 2.10 kJ mol(-1), respectively. The low value of E(a) shows that Cu(II) and Pb(II) adsorption process by MOCS may involve a non-activated chemical adsorption and a physical sorption.