激光剥蚀电感耦合等离子体质谱快速分析水系沉积物主量及痕量元素

基于193 nm ArF准分子激光器与四级杆电感耦合等离子体质谱联用,我们描述了固体样品分析中定量校准的基本原理,提出了一个简单,快速、同时分析水系沉积物中主量及痕量元素的方法:无内标校准法.分析了水系沉积物中主、痕量共52种元素.对水系沉积物标准参考物质GSD-4的分析,结果与推荐值具有良好的一致性,相对误差<15%的有46个元素,<10%的有36个元素;大多数元素的相对标准偏差<10%.结果表明,运用多个外标和无内标校准法,能够对水系沉积物样品进行多元素快速、同时分析,分析结果的准确度优于传统的外标-内标结合校准法.     

激光烧蚀-等离子体质谱结合归一定量方法原位线扫描检测石榴石多种元素

探讨了基体归一定量技术在实际应用中存在的问题.外标结合内标归一校正法避免了内标法中需要采用其它微区技术测定内标含量的繁琐步骤,可方便地用于具有环带结构等难以找到均匀分布的内标元素的地质样品的元素空间分布测定,解决了在采用直接外标法进行基体归一时,不能同时采用多外标进行校正的缺陷.激光线扫取样的最大优势是快速、省时.采用线扫的激光取样方式,结合归一定量技术,对具有环带结构的天然石榴石样品中的45种元素进行了分析测定,并与传统的激光打坑结果作对比,结果令人满意.     

玻璃标样结合硫内标归一定量技术在激光剥蚀-等离子体质谱分析硫化物矿物中的应用

以硬石膏矿物标样中Ca相对于S的灵敏度因子为基准,将玻璃标样中主量和痕量元素相对于Ca的灵敏度因子转换成元素相对于S的灵敏度因子,建立了多玻璃标样结合硫内标归一定量技术分析硫化物单矿物多元素的新方法。利用本方法分析了美国合成多金属硫化物矿物标样MASS-1中20种元素,主量元素分析结果的相对误差小于10%,痕量元素分析结果几乎都落在给定值±不确定度范围内。利用本方法对12个硫化物单矿物分析结果表明,绝大多数主量元素含量测定值的相对误差小于10%,且多数主量元素甚至优于以MASS-1为外标、内标归一定量法及内标校准法分析结果,而痕量元素与MASS-1校准结果较为一致。本方法克服了基体不匹配的问题,能比较准确地定量分析硫化物矿物中的主成分S,可用于定量校准硫化物矿物。     

激光剥蚀-电感耦合等离子体质谱:双外标结合基体归一定量校准策略

定量校准策略是激光剥蚀电感耦合等离子体质谱(AICP-MS)分析技术的重要组成部分,直接影响分析数据的质量.本研究评估了现有玻璃标准物质定值不确定度的相对大小,并探究了NIST、MPI-DING和USGS系列玻璃标准物质之间的基体效应.结果表明,NIST610的定值不确定度优于其它玻璃标准物质,在本实验条件下,NIST、MPI-DING和USGS系列玻璃标准物质之间的基体效应可忽略不计.在此基础上提出了双外标结合基体归一定量校准策略,外标分别为NIST610和StHs6/80-G.此策略克服了由于NIST610主量成分与地质样品差别大而造成的主量元素准确度差以及StHs6/80-G中某些微量元素含量低、定值不确定度较大等缺点.对比采用3种定量校准策略(单外标NSIT610基体归一法、单外标StHs6/80G基体归一法和双外标基体归一法)校准的ML3B-G数据可知,双外标基体归一法有效避免了单外标基体归一法的不足,并提高了分析数据的准确度.采用双外标结合基体归一定量校准策略校准了BCR-2G、CGSG-2和KL-2G中的主量元素和微量元素.结果表明,绝大多数分析数据在定值不确定度范围内,验证了此校准策略的实用性.同时,本研究得到的主量微量元素数据进一步补充了BCR-2G、CGSG-2和KL-2G的定值数据库.     

激光剥蚀电感耦合等离子体质谱法测定碳化硅器件中杂质元素

采用激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS),以NIST玻璃标准物质制作校准曲线,29Si为内标,相对灵敏度因子(RSF)校准标样和样品间的基体效应,对碳化硅陶瓷器件中9种痕量元素(B,Ti,Cr,Mn,Fe和Ni等)进行定量测定。选择线性扫描方式,激光剥蚀孔径为150μm,氦气和氩气流量为0.7 L/min时,信号稳定性和灵敏度最佳。经内标校准后,各元素标准曲线的线性有较大改善,线性相关系数为0.9981~0.9999。以建立的方法对碳化硅标准参考物质(BAM-S003)中的痕量元素进行测定,并与标准参考值进行对比,结果一致,证实了LA-ICP-MS方法应用于碳化硅样品检测的准确性和有效性。采用本方法定量测定碳化硅器件中痕量元素,结果与辉光放电质谱法(GD-MS)测定的结果比较一致。元素B,Ti,Cr,Mn,Fe,Ni,Cu,Sr和La的检出限为0.004~0.08 mg/kg,相对标准偏差(RSD)小于5%。     

基体分离-电感耦合等离子体质谱法测定高纯硒中13种杂质元素

采用基体分离-电感耦合等离子体质谱法（ICP-MS）测定高纯硒中13种痕量杂质元素含量,优化了试验条件.利用二氧化硒在真空条件下升华温度低的特点挥发基体硒,选择合适的内标元素,考察基体效应的影响.结果表明,选择Cs作为待测元素的内标更合适.测定硒残留量小于100 μg/mL的样品,不影响各待测元素.方法检出限为0.007~0.033 μg/g,RSD为5.7%~19%,加标回收率在90.2%~115%之间,可以满足高纯硒中痕量杂质元素含量的测定.     

基体匹配—电感耦合等离子体质谱(ICP-MS)法测定萤石精矿中痕量有害元素

为向萤石精矿质量检测和环境监管提供可靠的数据支撑，采用基体匹配—电感耦合等离子质谱法测试萤石精矿中痕量有害元素铜、锌、砷、镉和铅的含量。利用硝酸溶解分析纯碳酸钙后，经ICP-MS测试溶液中钙元素含量与理论值偏差约6%。钙溶液经不同倍率稀释后配置基体浓度为1000、2000和5000mg/L多元素标准溶液，在ICP-MS测试不同基体浓度混合标准溶液的内标回收率稳定性和IF/BK压降情况后，确定了1000 mg/L的最佳基体浓度。在传统四酸消解法基础上，通过改变加酸顺序、用量和温控水平，实现对萤石精矿的完全消解。消解实验中，同步设置消解加标、过程空白和空白加标实验。萤石精矿在消解定容及适度稀释后，溶液中离子浓度与复杂基体标准溶液的最佳基体浓度接近。在复杂基体标准溶液及样品消解液测试中，采用He模式的碰撞反应池技术，选用72Ge、115In和175Lu作为内标元素。结果显示：各元素标准曲线线性大于0.9995，各样品内标回收率在80%-110%范围波动，表明基体匹配联合内标校正，有效消除了复杂样品测试中的非质谱和质谱干扰。消解实验中未产生过量的元素沉淀或挥发损失，加标样品各有害元素回收率在90%-120%。质控样品各元素含量测试误差在15%以内。此测试方法中铜、锌、砷、镉和铅的检出限分别为4.81、8.65、17.91、0.49和2.84 μg/L，可满足复杂基体样品中痕量元素含量的准确测试需求。     

-电感耦合等离子体质谱法测定硅锰冶炼渣中8种金属元素

实验采用HCl-HNO₃-HF-HClO₄混合酸为消解体系对样品进行前处理,加入1.0 mL盐酸羟胺溶液(100 g/L)溶解残渣,选择合适的同位素,以¹⁰³Rh为内标测定Cr、Co、Ni、Cu、Zn和Cd,以¹⁹³Ir为内标测定Tl和Pb,建立了电感耦合等离子体质谱(ICP-MS)法测定硅锰冶炼渣中8种重金属元素的方法。实验发现,样品前处理选择HCl∶HNO₃∶HF∶HClO₄=5∶5∶5∶1,并在复溶阶段加入1.0 mL盐酸羟胺溶液(100 g/L)可以完全消解样品,实验采用KED模式和干扰系数校正法消除质谱干扰,样品中待测元素的测定结果不受基体成分的干扰。通过绘制校准曲线及测定流程空白,各元素校准曲线的相关系数均大于0.9999,方法检出限为0.006~0.19 mg/kg,方法定量限为0.018~0.57 mg/kg。对硅锰渣实际样品进行测定,各元素的相对标准偏差(RSD,n=11)在0.83%~4.1%,加标回收率为94.7%~106%;经过人员比对实验,相对偏差为-4.54%~4.24%。测定结果稳定可靠,能满足硅锰冶炼渣中8种微量金属元素含量的分析检测要求。     

等离子体质谱法测定地质样品中痕量稀土元素的基体效应及多原子离子干扰的校正研究

采用模拟地质样品中稀土元素间天然组成比的基体匹配校正标准溶液进行外标校正,有效地抑制了地质样品分析中的基体效应;以¹¹⁵In-¹⁰³Rh双内标元素校正,监控和校正分析信号的短期和长期漂移;通过单个稀土元素及钡的氧化物、氢氧化物的测定计算出等效的干扰浓度,进而校正了稀土元素分析中多原子离子干扰.建立了地质样品中痕量稀土元素测定中基体效应及多原子离子干扰的校正方法,通过对5个标准参考物质的分析,定量测定限为0.0090.133μg·g^-1,RSD小于5%.     

碱熔-电感耦合等离子体原子发射光谱(ICP-AES)法测定水泥标准物质中的氧化物含量

电感耦合等离子体原子发射光谱(ICP-AES)法与内标法的结合扩展了ICP-AES法的分析范围。采用氢氧化钠熔融样品,ICP-AES-内标法测定各类水泥标准物质样品中SiO_2、Al_2O_3、TFe_2O_3、MgO、TiO_2等氧化物的含量。实验结果表明,标准物质测定值与标准值吻合,6次平行样品测定相对标准偏差小于1.4%。方法一次熔样,纵向测定主常量元素,操作简单,快速,准确,为水泥标准物质的研制提供了另一种定值方式。     

Quantitative multi-element mapping of ancient glass using a simple and robust LA-ICP-MS rastering procedure in combination with image analysis

The surface of two glass artefacts in mosaic style, probably fragments of conglomerate glass bowls dating back two millennia, was investigated by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). By rastering with the laser beam over a selected area of the surface of the glass artefacts, elemental oxide maps were generated. Quantification of the elemental oxides in the maps was achieved using a so-called sum normalization procedure, summating the elements—54 in total—as their oxides to 100% (w/w), without using an internal standard and applying only one external standard (NIST SRM glass 610). This results in a robust mapping procedure which automatically corrects for drift and defocusing issues. Sum normalization was applied to each pixel in the map separately and required a custom source code to process all the data in the tens of thousands of pixels to generate the elemental oxide concentration maps. The digital element maps generated upon rastering of the two glass artefacts are very compelling and are an excellent entry point to gain detailed insight into their fabrication and provenance using image analysis software for retrieval of localized elemental oxide concentrations and correlations.     

Direct Analysis of Laminated Dolomite and Zircon by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

Distributions of elements in laminated dolomite and zircon crystal were obtained by laser ablation inductively coupled plasma mass spectrometry. The variation of signal intensity was normalized by an internal standard method using the sum of the signals of Ca and Mg which was assumed to be constant in every position for the dolomite sample and using Zr signal for the zircon sample. The concentrations of elements change correspondingly across the laminated structure of dolomite. U and Th show a zoned distribution in the zircon crystal.     

A new strategy of solution calibration in laser ablation inductively coupled plasma mass spectrometry for multielement trace analysis of geological samples

Because multielement trace analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is often limited by the lack of suitable reference materials with a similar matrix composition, a novel quantification strategy using solution calibration was developed. For mass spectrometric multielement determination in geological samples a quadrupole-based LA-ICP-MS is coupled with an ultrasonic nebulizer (USN). In order to arrange matrix matching the standard solutions are nebulized with a USN during solution calibration and simultaneously a blank target (e.g. lithium borate) is ablated with a focused laser beam. The homogeneous geological samples were measured using the same experimental arrangement where a 2% nitric acid is simultaneously nebulized with the USN. Homogeneous targets were prepared from inhomogeneous geological samples by powdering, homogenizing and fusing with a lithium borate mixture in a muffle furnace at 1050 degrees C. Furthermore, a homogeneous geological glass was also investigated. The quantification of analytical results was performed by external calibration using calibration curves measured on standard solutions. In order to compare two different approaches for the quantification of analytical results in LA-ICP-MS, measured concentrations in homogeneous geological targets were also corrected with relative sensitivity coefficients (RSCs) determined using one standard solution only. The analytical results of LA-ICP-MS on various geological samples are in good agreement with the reference values and the results of other trace analytical methods. The relative standard deviation (RSD) for trace element determination (N = 6) is between 2 and 10%.     

A new strategy of solution calibration in laser ablation inductively coupled plasma mass spectrometry for multielement trace analysis of geological samples

Because multielement trace analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is often limited by the lack of suitable reference materials with a similar matrix composition, a novel quantification strategy using solution calibration was developed. For mass spectrometric multielement determination in geological samples a quadrupole-based LA-ICP-MS is coupled with an ultrasonic nebulizer (USN). In order to arrange matrix matching the standard solutions are nebulized with a USN during solution calibration and simultaneously a blank target (e.g. lithium borate) is ablated with a focused laser beam. The homogeneous geological samples were measured using the same experimental arrangement where a 2% nitric acid is simultaneously nebulized with the USN. Homogeneous targets were prepared from inhomogeneous geological samples by powdering, homogenizing and fusing with a lithium borate mixture in a muffle furnace at 1050?°C. Furthermore, a homogeneous geological glass was also investigated. The quantification of analytical results was performed by external calibration using calibration curves measured on standard solutions. In order to compare two different approaches for the quantification of analytical results in LA-ICP-MS, measured concentrations in homogeneous geological targets were also corrected with relative sensitivity coefficients (RSCs) determined using one standard solution only. The analytical results of LA-ICP-MS on various geological samples are in good agreement with the reference values and the results of other trace analytical methods. The relative standard deviation (RSD) for trace element determination (N = 6) is between 2 and 10%.     

External calibration strategy for trace element quantification in botanical samples by LA-ICP-MS using filter paper

The use of reference solutions dispersed on filter paper discs is proposed for the first time as an external calibration strategy for matrix matching and determination of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn in plants by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The procedure is based on the use of filter paper discs as support for aqueous reference solutions, which are further evaporated, resulting in solid standards with concentrations up to 250 μg g⁻¹ of each element. The use of filter paper for calibration is proposed as matrix matched standards due to the similarities of this material with botanical samples, regarding to carbon concentration and its distribution through both matrices. These characteristics allowed the use of ¹³C as internal standard (IS) during the analysis by LA-ICP-MS. In this way, parameters as analyte signal normalization with ¹³C, carrier gas flow rate, laser energy, spot size, and calibration range were monitored. The calibration procedure using solution deposition on filter paper discs resulted in precision improvement when ¹³C was used as IS. The method precision was calculated by the analysis of a certified reference material (CRM) of botanical matrix, considering the RSD obtained for 5 line scans and was lower than 20%. Accuracy of LA-ICP-MS determinations were evaluated by analysis of four CRM pellets of botanical composition, as well as by comparison with results obtained by ICP-MS using solution nebulization after microwave assisted digestion. Plant samples of unknown elemental composition were analyzed by the proposed LA method and good agreement were obtained with results of solution analysis. Limits of detection (LOD) established for LA-ICP-MS were obtained by the ablation of 10 lines on the filter paper disc containing 40 μL of 5% HNO₃ (v v⁻¹) as calibration blank. Values ranged from 0.05 to 0.81  μg g⁻¹. Overall, the use of filter paper as support for dried aqueous standards showed to be a useful strategy for calibration and plant analysis by LA-ICP-MS.     

Determination of trace elements in zeolites by laser ablation ICP-MS

Laser ablation inductively coupled plasma mass spectrometry using a quadrupole-based mass spectrometer (LA-ICP-QMS) was applied for the analysis of powdered zeolites (microporous aluminosilicates) used for clean-up procedures. For the quantitative determination of trace element concentrations three geological reference materials, granite NIM-G, lujavrite NIM-L and syenite NIM-S, from the National Institute for Metallurgy (South Africa) with a matrix composition corresponding to the zeolites were employed. Both the zeolites and reference materials were fused with a lithium borate mixture to increase the homogeneity and to eliminate mineralogical effects. In order to compare two different approaches for the quantification of analytical results in LA-ICP-MS relative sensitivity coefficients (RSCs) of chemical elements and calibration curves were measured using the geostandards. The experimentally obtained RSCs are in the range of 0.2-6 for all elements of interest. Calibration curves for trace elements were measured without and with Li or Ti as internal standard element. With a few exceptions the regression coefficients of the calibration curves are better than 0.993 with internal standardization. NIM-G granite reference material was employed to evaluate the accuracy of the technique. Therefore, the measured concentrations were corrected with RSCs which were determined using lujavrite reference material NIM-L. This quantification method provided analytical results with deviations of 1-11% from the recommended and proposed values in granite reference material NIM-G, except for Co, Cs, La and Tb. The relative standard deviation (RSD) of the determination of the trace element concentration (n = 5) is about 1% to 6% using Ti as internal standard element. Detection limits of LA-ICP-QMS in the lower microg/g range (from 0.03 microg/g for Lu, Ta and Th to 7.3 microg/g for Cu, with the exception of La) have been achieved for all elements of interest. Under the laser ablation conditions employed (lambda: 266 nm, repetition frequency: 10 Hz, pulse energy: 10 mJ, laser power density: 6 x 10(9) W/cm2) fractionation effects of the determined elements relative to the internal standard element Ti were not observed.     

Trace analysis of high-purity graphite by LA-ICP-MS

Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a very efficient and sensitive technique for the direct analysis of solids. In this work the capability of LA-ICP-MS was investigated for determination of trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose of quantifying the analytical results. Doped trace elements, concentration 0.5 microg g(-1), in a laboratory standard were determined with an accuracy of 1% to +/- 7% and a relative standard deviation (RSD) of 2-13%. Solution-based calibration was also used for quantitative analysis of high-purity graphite. It was found that such calibration led to analytical results for trace-element determination in graphite with accuracy similar to that obtained by use of synthetic laboratory standards for quantification of analytical results. Results from quantitative determination of trace impurities in a real reactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all elements of interest were determined in the low ng g(-1) concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite with LA-ICP-MS under wet plasma conditions, because the lower background signal and increased element sensitivity.     

Determination of Platinum Group Elements in Sulfide-Containing Minerals by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry with Synthetic Calibration Standards

This paper develops sulfide calibration standards for quantitative determination of platinum group elements in natural sulfide-containing minerals by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). A series of sulfide calibration standards containing different concentrations of platinum group elements were prepared using a home-made high temperature furnace. Homogeneity of element distribution expressed as the RSD of signal intensity were less than 10%. The effective concentrations of platinum group elements in synthetic calibration standards were obtained both by pneumatic nebulization ICP-MS and by LA-ICP-MS. Relative percentage differences of these results obtained by two methods were mainly less than 11%. The synthetic calibration standards were then employed as calibrators for quantitative determination of platinum group elements in two natural chalcopyrite samples. The valid results demonstrated that our synthetic standards could be considered for quantitative microanalysis of platinum group elements in natural sulfide-containing minerals.