Gaseous sample introduction for the determination of silicon by ICP-AES

The generation of volatile species of silicon as a means to introduce silicon into an inductively coupled plasma has been studied. It is based on the reaction between silicon and fluoride ions in sulfuric acid media and it was carried out using different flow injection mountings. The first mounting works with an injection of 100 μL concentrated sulfuric acid and 150 μL silicon standard solution in a continuous 0.05 mol L^–1 NaF solution flow. The method shows a linear response between the intensity of emission at 251.611 nm line and the silicon concentration from 0.1 to 200 μg mL^–1, with a reproducibility of 2% and a detection limit of 0.004 μg mL^–1. The second mounting produces the volatile species by the reaction between two opposed aerosol flows in a home-made nebulization chamber. This chamber has a Cross-Flow and a Meinhard nebulizer at either end. A linear response ranging from 0.1 to 1000 μg mL^–1 of silicon solution is obtained and the reproducibility rises to 8%.The detection limit reached is 0.02 μg mL^–1. The silicon content in real water samples was determined by applying both the above-mentioned methods and a third method for reference. Received: 6 November 1996 / Revised: 19 December 1996 / Accepted: 3 January 1997     

ICP-AES法测定出口工业硅中11种杂质元素

利用ICP-AES分析技术,对试样溶解方法,元素分析谱线,共存元素干扰,仪器分析参数,无机酸介质影响等因素进行了研究,确定了最佳工作条件,建立了可同时测定出口金属硅中11种杂质元素的简单、快速和适用的分析方法,结果表明,该方法线性范围宽,检出限低,准确性高,操作步骤简单,11个元素测定回收率在85％～105％之间,相对标准偏差在1．9％～8．1％之间。     

Determination of cadmium in water by ICP-AES with on-line adsorption preconcentration using DPTH-gel and TS-gel microcolumns

Two flow injection inductively coupled plasma atomic emission spectrometric methods for the preconcentration and determination of trace amounts of cadmium in sea-water and waste-water samples are described based on the adsorption of the metal ion on a micro-column placed in the injection valve of the FI manifold and packed with silica gel funtionalised with 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH-gel) and silica gel functionalised with methylthiosalicylate (TS-gel), respectively. Various parameters and chemical variables affecting the preconcentration and determination of this metal by ICP-AES are evaluated. The DPTH-gel preconcentration method has a linear calibration range from 5 to at least 100 ng ml(-1) of cadmium, with a R.S.D. of 1.1% for ten independent analyses of 100 ng ml(-1), a detection limit of 1.1 ng ml(-1) and a throughput of 40 samples per hour using a 60 s preconcentration time. The TS-gel preconcentration method shows a linear range between 10 and 100 ng ml(-1), with a R.S.D. of 2.5% for ten independent analyses of 100 ng ml(-1), a detection limit of 4.3 ng ml(-1) and a sample throughput of 24 samples per hour for a preconcentration time of 120 s. Validation was carried out against a certified reference water sample and by determining the analyte content in spiked synthetic sea-water, sea-water and waste-water.     

Determination of silicon in high siliconnickel alloys by ICP-AES after dissolving in nitric-hydrofluoric acids

Silicon was determined by ICP-AES in high Si-Ni alloys dissolved in HNO₃-HF. The interference by Si signals originating from the corrosion of the torch by HF was eliminated by keeping it almost constant. The relative standard deviation was within ±1%.     

Determination of sodium tripolyphosphate in meat samples by capillary zone electrophoresis with on-line isotachophoretic sample pre-treatment

The usefulness of zone capillary electrophoresis (CZE) in combination with isotachophoresis (cITP) as on-line preconcentration technique was examined for analysis of tripolyphosphate (STPP) in meat and meat products. The mean concentrations of STPP in different types of meat products varied from 39 mg P₂O₅/100 g to 219 mg P₂O₅/100 g, these values are below the legal requirements. The detection (LOD) and quantification (LOQ) limits for STPP in extracted solutions were 0.80 mg P₂O₅/dm³ and 2.69 mg P₂O₅/dm³, respectively. Obtained results were compared with the Kjeldahl method. Accuracy (97.4-98.3%) was determined using recovery assay based on standard additions method. Precision was evaluated by within-day R.S.D. (1.40-2.19%), between-days R.S.D. (3.00-3.82%) and demonstrates the benefit of using this procedure for the routine analysis of STPP in meat and their products. The F-Snedecor test was employed to compare the precision of the used methods and calculated F-test values (4.00, 6.13) were less than the theoretical (6.39).     

Phase analysis of high-temperature superconductors by selective dissolution combined with ICP-AES

Summary An apparatus for the selective dissolution as a chemical method of phase analysis and its operating conditions are described. Using ICP-AES as determination method an example for the YBCO system is found in the phase YBa_2–0.04Cu_3+0.03O_x and a BSCCO system is found in three phases of 35.6% Bi₂(Sr,Ca)_4–0.08Cu_3–0.05O_x, 30.1% Bi₂(Sr,Ca)_3–0.09Cu_2–0.08O_x and 34.3% Bi₂(Sr,Ca)_2–0.07Cu_1–0.05O_x.     

Analysis of silicon carbide powders with ICP-MS subsequent to sample dissolution without and with matrix removal

ICP-MS has been employed for the analysis of silicon carbide powders in connection with high pressure acid decomposition without and with matrix removal by evaporation. The powder is decomposed by treatment of a 250 mg sample with a mixture of HNO₃, H₂SO₄ and HF. Prior to the analyses with ICP-MS the solutions have to be diluted to a matrix concentration of 500 g/ml related to SiC in order to realize full long-term precision. The results obtained for Li, B, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Sr, Y, Zr, Nb, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Hf, Ta, W, Tl, Pb, Bi, Th and U in SiC powder S-933 are shown to be in good agreement with those of independent methods, such as INAA, ICP-AES with slurry atomization and ICP-AES subsequent to sample decomposition. For extending the use of ICP-MS to elements such as Mg, Ca, Sc and Ti at the relevant concentrations in SiC powders, a more effective matrix removal by evaporation of the decomposition solution to near dryness has been successfully applied. Its advantages have been proven by the results of high resolution ICP-MS. It has been found by analyses of the treated sample solutions for the residual Si and C with ICP-MS that over 99% of the matrix and also of the acids used for decomposition are removed. For B, Al and Fe losses were found to occur at concentration levels of some g/g, 200 g/g and 300 g/g, respectively, and all other elements were detected with very good recoveries. For all 36 elements investigated in this work the detection limits could be improved from the ng/g to the pg/g range by removal of the matrix. The analytical range could be improved, in particular for In, Tl, Bi and U.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday     

Determination of nickel in biological samples by ETA-AAS and ICP-AES after acidic dissolution (with microwave heating and preconcentration by liquid-liquid extraction)

The determination of nickel by ETA-AAS and ICP-AES in biological samples with prior extraction into methyl isobutyl ketone with 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide as extracting reagent is described. Microwave dissolution in closed teflon vessels has been used for the dissolution of biological materials. At least three samples can be decomposed simultaneously with a preset heating programme. Results of analyses of some certified biological reference materials are given.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量的方法。为避免复杂基体、溶样时间对测试结果产生干扰,采用标准加入法进行定量分析。通过实验,确定了溶样用盐酸的浓度、ICP仪器参数以及待测元素的分析线。考察了标准曲线的相关性、精密度和准确度等分析指标。结果表明,标准曲线成线性关系(R=0.998 8),检测结果的相对标准偏差仅为1.3%,与现有的国家标准分析方法——碘酸钾滴定法和X射线荧光光谱法进行对比实验,测量结果基本一致。     

ICP-AES测定硅锰中的磷

采用电感耦合等离子体-原子发射光谱法(ICP-AES)研究了硅锰合金中磷的测定,考察了试样的分解、分析谱线的选择、干扰元素的影响及精密度和准确度等影响的有关因素,其测定结果与国家标准方法一致.磷的分析谱线采用214.914 nm的测定结果最好;该方法的检出限为0.003％,回收率为96.9％～101.6 ％.     

ICP-AES法测定钢中的铈

建立了离子体发射光谱仪测定钢中铈元素的方法。为消除共存元素对铈分析游线的光谱干扰,选择Ce413．380nm作为分析线,铈含量在0．005％-0．50％之间工作曲线线性良好。对于含量范围在0．005％-0．10％的铈元素,回收率为85．6％-12．5％,测定结果的相对标准偏差小于9．74％（n=8）;对于含量范围在0．10％-0．50％的铈元素,回收率为99．5％-103．0％,测定结果的相对标准偏差小于3．52％（n=8）。该方法适宜钢中含量范围在O．005％-0．50％的铈元素的测定。     

ICP-AES法测定矿石中的BeO

报道了采用ICP－AES法测定矿石中的BeO。对试样的溶解进行了选择；考察了其体和无机酸对测定的影响。采用基体匹配法进行测定。在优化条件下，对三个试样进行测定，其相对标准偏差（n=9）为0.28%；回收率为97％－103％。     

Determination of trace amounts of rare earth and other elements in rice samples by ICP-AES with sample introduction by tungsten-coil electrothermal vaporization

Summary A device with tungsten-coil electrothermal vaporization for sample introduction into ICP has been proposed. It was applied to the determination of trace amounts of rare earth and other elements in rice samples. Several influencing factors were investigated in detail, such as drying and vaporization parameters, carrier gas flow rate, volume of vaporization chamber and matrix effects. Under optimal experimental conditions, the detection limits for Mg, Cu, Mn, Cr, Fe, Co, Ni and eight rare earth elements are of the order of 10⁻⁹−10⁻¹¹ g. The detection limits for the rare earth elements tested by the present method are comparable to and, in most instances, exceed those for the GFAAS and conventional pneumatic nebulisation-ICP-AES. A precision with RSD<6% was obtained.     

Determination of sulphur by electrolytic hydrogenation

Certain sulphur compounds such as thiosulphuric acid, polythionic acids, thiocyanic acid, thioureas, thioamides and 2-mercapto-acids are readily electrolytically hydrogenated in 1N sulphuric acid to form hydrogen sulphide which is absorbed in potassium hydroxide solution and titrated with o-hydroxymercuribenzoic acid in the presence of dithizone as indicator. The electrolytic cell consists of a lead anode in 5N sulphuric acid, a porous ceramic tube as diaphragm, and a cathode made of soft iron. The first-order rate-constants of hydrogenation and the results of determination of sulphur in some sulphur compounds are presented. The limit of determination is 0.1 ppm.     

自动消解仪—ICP法测定水系沉积物中6种重金属元素

建立了自动消解仪-电感耦合等离子体发射光谱法(ICP-OES)同时测定水系沉积物中Cu、Zn、Ni、Cr、Pb、Co六种元素含量的方法。该方法的相关系数好、检出限低。方法经国家标准物质(GBW07361)验证,准确度和精密度均能达到环境监测分析的要求,为水系沉积物中重金属元素含量的测定提供了简单可靠的分析方法。     

ICP-AES测铣刀中的钴元素

铣刀作为常用的切削工具,其需求量很大.它的主要成分是硬质合金--一种由钨、钴等稀有金属元素组成的高硬度、高强度的材料.硬质合金是一种优良的工具材料和结构材料,目前它的生产原料主要是纳米碳化钨-钴(WC-Co)复合粉末,碳化钨(WC)是一种硬度高、热稳定性和耐磨性好的硬质合金材料.添加稀有金属钴(Co)使得钴钨合金的耐磨耐蚀性能进一步提高,有效地解决了硬质合金的硬度和强度之间的矛盾.通过化学法测试其钴含量,分析手续繁琐,周期较长.而用ICP-AES直接测定硬质合金中的钴元素尚未见报道.为了适应检验快速准确的实际需要,实验用ICP-AES对硬质合金中钴元素的样品前处理及测定方法进行了研究.对实际样品进行ICP-AES法与其他化学法对比实验测定,结果表明该方法快速、简便、准确,这对于铣刀日常检验的光谱分析具有重要的实际意义.     

Metal complex separation with on-line sample preconcentration in micellar electrokinetic chromatography.

Micellar electrokinetic chromatography (MEKC) using a cationic surfactant as a pseudostationary phase was examined to separate anionic metal cyclohexane-1,2-diaminetetraacetic acid (CDTA) complexes. Cetyltrimethylammonium chloride (CTAC) was employed as the cationic surfactant micelle, its addition leading to EOF reversal. Cu(II), Co(II), Zn(II), Mn(II) and Pb(II) were used as test analytes, and the complete separation was obtained by MEKC. On-line sample preconcentration by sweeping was also examined to improve the detection sensitivity. From 15- to 42-fold increases in the detection sensitivity in terms of the peak heights were obtained by sweeping with a cationic micelle in the presence of high EOF. The limits of detection were in the range (0.6 - 1.8) x 10(-6) M with UV detection without any off-line preconcentration step.     

复合熔剂熔融-ICP-AES法测定萤石中钾钠硅铁磷

采用四硼酸锂偏硼酸锂复合熔剂高频熔融炉熔融硝酸浸取方式溶解萤石,用已知含量萤石标准物质制作标准工作曲线,应用ICP-AES法联合测定萤石中硅、磷、钾、钠、铁组分含量。选择两条谱线进行分析,方法检出限在0.025～8.7mg/g之间,样品检测5次的相对标准偏差小于17.98％,测定值与证书值相吻合。     

微波消解–电感耦合等离子体光谱法测定预包装食品中的钠含量

采用微波消解样品,建立电感耦合等离子体光谱(ICP–AES)测定预包装食品中钠含量的方法。结果表明,钠的质量浓度在0~100 mg/L范围内与光谱强度呈良好线性关系,相关系数为0.999 9,钠的检出限为0.006 mg/L,加标回收率为95.5%~106.2%,测定结果的相对标准偏差为2.43%(n=6)。测定大米、菠菜、茶叶、脱脂奶粉和猪肉5个标准物质对方法进行验证,测定值与标准值吻合。该方法操作简便,适用于预包装食品中钠含量的检测。