Slurry nebulization ICP-AES spectrometry method for the determination of tin in organotin(IV) complexes

This paper proposes a quick, novel method for tin determination in organotin chemicals by slurry nebulization inductively coupled plasma atomic emission (ICP-AES) spectrometry. The method was tested by the measurement of five organotin carboxylate complexes of known composition for obtaining simple stoichiometric data. The slurries were prepared by first dissolving the organotins in an adequate solvent (methanol, pyridine or acetone) well miscible with water and then adding this solution drop-by-drop to a 0.005% TX-100 tenzide solution while maintaining intensive mixing. Dynamic laser light scattering experiments showed that the average equivalent particle size in the resulting slurry was ≈0.3 μm for all samples and solvents. Under suitable ICP-AES measuring conditions, the signal recoveries were found to be between 101.8 and 106.6%, which allowed direct nebulization and calibration against aqueous solutions. Typically, 70 μg l⁻¹ detection limit and 1–5% relative S.D. on five replicates can be achieved by the described method.     

Optimization of slurry nebulization inductively-coupled plasma atomic emission spectrometry for the analysis of ZrO2-powder

The optimization and use of ICP-AES with slurry nebulization for the direct analysis of ZrO₂-powder is described. The powder samples are dispersed in water, acidified to pH 2 and the slurry is fed into a Babington nebulizer. The effects of grain size, pH of the suspending medium and standing time on the stability of the slurry are discussed. For the optimization of the ICP operating conditions, a simplex technique is applied and for this purpose three types of objective functions were examined. Identical behaviour of slurries and solutions with the same matrix concentrations in the ICP-AES is achieved for powders with particle sizes lower than 10 m; in the latter case calibration can be performed by standard addition with aqueous solutions. The detection limits for Al, B, Ca, Cu, Fe, Mg, Mn, Na, Ti, V. Y are 0.03 g/g to 10 g/g and the standard deviation is generally lower than 10%. Six commercially available ZrO₂ powders are analyzed by slurry nebulization ICP-AES and the results were found to agree well with those obtained by ICP-AES after chemical decomposition of the samples.On leave from Department of Analytical Chemistry, Technical University, PL-00-664 Warsaw, Poland     

原子光谱分析中的浆液雾化进样

提出了ICP-AES／MS方法中浆液雾化进样问题。叙述了均匀与稳定的浆样制备方法,包括使用添加剂和pH调节。讨论了颗粒大小分布、zeta电位测定等浆样稳定性的表征方法。评述了校准曲线法、标准加入法和本征内标法等校准方法。     

Modelling of the evaporation behaviour of particulate material for slurry nebulization inductively coupled plasma atomic emission spectrometry

This paper is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta, Part B (SAB). This hardcopy text, comprising the main body and an appendix, is accompanied by a disk with programs, data files and a brief manual. The main body discusses purpose, design principle and usage of the computer software for modelling the evaporation behaviour of particles in inductively coupled plasma atomic emission spectrometry (ICP-AES). Computer software has been developed in FORTRAN 77 language in order to simulate the evaporation behaviour of particles of refractory materials such as encountered in the analysis of advanced ceramic powders by slurry nebulization inductively coupled argon plasma atomic spectrometry. The program simulates the evaporation of single particles in the inductively coupled plasma and also enable it to calculate on the base of a given particle size distribution the evaporation behaviour of all the particles contained in a sample. In a so-called “intensity concept”, the intensity is calculated as a function of the observation height in order to determine recovery rates for slurries compared with aqueous solutions. This yields a quick insight whether a calibration with aqueous solutions can be used for analysis of slurries of a given powder by slurry nebulization ICP-AES and also is a help in determining the optimal parameters for analyses of powders by means of slurry nebulization ICP-AES.Applications for the evaporation of Al₂O₃ and SiC powders document the usefulness of the model for the case of a 1.5 kW argon ICP of which the temperature at 8 mm above the load coil has been determined to be 6100 K. The model predicts the maximum particle size for SiC and Al₂O₃ that can be transported (10–15 μm) and evaporated for a given efficiency under given experimental conditions. For both Al₂O₃ and SiC, two ceramic powders of different grain size were investigated. The median particle sizes cover the range typical of ceramic powders. Investigations were made for SiC A 10 (median particle size 2.2 μm), SiC F1200 (4.3 μm) and Al₂O₃ AKP 30 (< 1.9 μm) and Al₂O₃ Cilas 715 (3.0 μm), respectively, in which particles with diameters of up to 23 μm still are found.     

Determination of Ga, Ge, As, Se and Sb in fly ash samples by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Ga, Ge, As, Se and Sb in fly ash samples. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. Pd and ascorbic acid were used as the mixed modifiers to enhance the ion signals. This method has been applied to determine Ga, Ge, As, Se and Sb in NIST SRM 1633a and 1633b coal fly ash reference materials and a fly ash sample collected locally. Since the sensitivities of the elements studied in slurry solution and aqueous solution were different slightly, analyte addition technique was used for the determination of Ga, Ge, As, Se and Sb in these samples. The As and Se analysis results of the reference materials agreed with the certified values. The results for which no certified value was available were also found to be in good agreement between the ETV-ICP-MS results and the reference values. The reference value was obtained by digesting the samples and analyzing the digested sample solutions by pneumatic nebulization Dynamic Reaction Cell™ (DRC) ICP-MS. The method detection limits estimated from analyte addition curves were about 0.23, 0.13, 0.17, 0.25 and 0.11 μg g⁻¹ for Ga, Ge, As, Se and Sb, respectively, in original fly ash samples.     

Simultaneous determination of hydride forming (As, Bi, Ge, Sb, Se, Sn) and Hg and non-hydride forming (Ca, Fe, Mg, Mn, Zn) elements in sonicate slurries of analytical samples by microwave induced plasma optical emission spectrometry with dual-mode sample introduction system

A slurry sampling method for the simultaneous determination of hydride forming (As, Bi, Ge, Sb, Se, Sn) and Hg and non-hydride forming (Ca, Fe, Mg, Mn, Zn) elements, without total sample digestion has been developed using the commercial dual-mode sample introduction system (MSIS) coupled with microwave induced plasma optical emission spectrometry (MIP-OES) from biological and environmental reference materials and real samples. The main advantage of this system is its simultaneous determination of elements that form volatile vapor species and elements that do not, without any instrumental changes. Optimization of reaction, nebulization and instrumental conditions was performed to characterize the new system. Slurry concentration up to 4% m/v (particles < 100 μm) prepared in 10% HNO₃ containing 100 μL of decanol, by application of ultrasonic agitation, was used with calibration by the standard addition technique. An ultrasonic probe was used to homogenize the slurry in the quartz cup just before its introduction into the reaction/nebulization system; the multimode sample introduction system (MSIS) combines the benefits of nebulization and vapor generation in a single device. Detection limits (LOD, 3σ_blank, peak area) of 0.07, 0.29, 0.25, 0.10, 0.12, 0.14, 0.11, 0.28, 0.42, 0.02, 0.21 and 0.34 μg g^− 1 were obtained for As, Bi, Ge, Sb, Se, Sn, Hg, Ca, Fe, Mg, Mn and Zn, respectively. The relative standard deviations were ca. 10%, adequate for slurry analysis. To test the accuracy, six certified reference materials were analyzed with the analyte concentrations mostly in the μg g^− 1 level. Measured concentrations are in satisfactory agreement with certified values for the biological reference materials (LUTS-1, DOLT-2) and environmental reference materials (PACS-1, GWB 07302, NIST 2710, NBS 1633b), all adequate for slurry sampling. The method was successfully applied to the determination of the elements in real samples (coal fly ash, lake sediment, sewage). The method requires small amounts of reagents and reduces contamination and losses.     

Determination of impurities in titanium nitride by slurry introduction axial viewed inductively coupled plasma optical emission spectrometry

A method of slurry nebulization for inductively coupled plasma optical emission spectrometry (ICP-OES) applied to the analysis of titanium niride(TiN) was reported. The TiN slurry sample was prepared with adding dispersant polyacrylate amine or polyethylene imine for the stabilization and homogenization of suspension, and the amount of additives was optimized. A Babington type cross-flow nebulizer with V-groove was used for nebulization of the slurry for avoidance of blockage from the particles. The stability of slurry was characterized via zeta potential measurement, scanning electron microscope observation, particle size distrbution measurement and signal stability testing. For nm size TiN, calibration curves could be established by aqueous standards and the analytical results were in good accordance with the alkaline fusion method. For μm size TiN, a negative deviation was observed for most of elements and this deviation can be corrected by using Ti intrinsic internal standard method.     

悬浮液进样电感藕合等离子体发射光谱中颗粒的输运和蒸发行为

以碳化硼为例,研究了悬浮液雾化进样中的粒子在传输和蒸发过程中的行为,并对分析结果出现负偏离的原因进行了详细探讨.对比悬浮液颗粒的原始粒径分布和经过传输过程后的粒径分布,获得到达等离子体的颗粒粒径上限小于10 Am.样品中存在的部分超大粒径的颗粒(d>>10 μm)会严重影响可传输区域颗粒(d<10 μm)的质量运输效率...     

On-line complexation/preconcentration system for the determination of lead in wine by inductively coupled plasma-atomic emission spectrometry with ultrasonic nebulization

An on-line lead preconcentration and determination system implemented with inductively coupled plasma-atomic emission spectrometry (ICP-AES) with ultrasonic nebulization (USN) in association with flow injection was studied. For the preconcentration of lead, a Pb-quinolin-8-ol complex was formed on-line at pH 6.8 and retained on Amberlite XAD-16 resin. The lead was removed from the microcolumn by countercurrent elution with nitric acid. A total enhancement factor of 225 was obtained with respect to ICP-AES with pneumatic nebulization (15.0 for USN and 15.0 for the column). The detection limit for Pb for the preconcentration of a 10 mL wine sample was 0.15 microg/L. The precision for 10 replicate determinations at a Pb level of 25 microg/L was a relative standard deviation of 2.5%, calculated from the peak heights obtained. The calibration graph obtained by using the preconcentration system for lead was linear with a correlation coefficient of 0.9995 for levels near the detection limit up to > or = 1000 microg/L. The method was successfully applied to the determination of lead in wine samples.     

Determination of nonmetals using ICP-AES-techniques

The determination of iodine, bromine, sulphur and phosphorus using different modes of sampling in ICP-AES is described. Detection limits in the range of some 10 gL^–1 have been obtained using directly aqueous solutions with pneumatic nebulization. The influence of several anions and metals has been investigated. The addition of methanol and ethanol have improved sensitivities but decreased signal-to-background ratios and detection limits due to extended blank values and increased standard deviations. Using ultrasonic nebulization the sensitivities and the detection limits could be enhanced for these elements in aqueous solutions, but a significant decrease in sensitivity has been observed using additives as methanol or ethanol. By coupling of pneumatic nebulization and gas generation of iodine by addition of oxidizing agents, the detection limits of iodine could be improved to 6 ngL^–1 at the 178.28 nm line. Electrothermal vaporization has sucessfully been applied for microsampling of nonmetals and ICP-AES determination. Using aqueous solutions without any modifier the following absolute detection limits at the S (180.73 nm), P (178.27 nm), I (178.28 nm) and Br (163.34 nm) lines have been obtained: 0.25 ng of S, 0.44 ng of P, 0.36 ng of I and 43 ng of Br.Dedicated to Professor Dr. K. Doerffel on the occasion of his 70th birthday     

Investigation of Matrix Effects for Direct Determination of Trace Metals in Seawater Using Direct Sample Insertion -Inductively Coupled Plasma Atomic Emission Spectrometry

Direct sample insertion (DSI) technique is an alternative sample introduction method for inductively coupled plasma atomic emission spectrometry (ICP-AES). Sample introduction efficiency of the DSI technique is 100% versus 3-5% for pneumatic nebulization and 30-40% for ultrasonic nebulization. DSI also has the ability to handle small volume (μL) of solution and small quantity (mg) of solids with little or no sample pre-treatment.     

等离子体原子光谱分析中溶液样品雾化进样方法的新进展

对近年来等离子体原子光谱分析中溶液样品引入方法的新进展作了综述，其中包括气动雾化法、超声雾化法、热雾化法、悬浆雾化法、高水压雾化法及电喷雾法等。文中还根据本课题组多年来的研究经验对每种方法的优缺点及其应用作了简要的介绍和评论。     

Inductively-coupled plasma atomic emission spectroscopic determination of trace impurities in ZrO2-powder

Four independent procedures including one using slurry nebulization ICP-AES were developed for the trace analysis of ZrO₂ powders. They were evaluated with respect to detection limits, blank values, interferences, accuracy and precision. For the procedures I–III ZrO₂ powder was decomposed by fusion with a 10-fold excess of NH₄HSO₄ and subsequent dissolution of the melt in either water or, after evaporation of NH₄HSO₄, in diluted HNO₃. In procedure I the solution was directly analyzed by ICP-AES, which was optimized with the aid of a simplex algorithm. In procedure II Zr was separated by extraction from 6 mol/l HNO₃ with a 0.5 mol/l solution of 2-thenoyltrifluoroacetone (TTA) in xylene. More than 99.5% of the Zr was removed and more than 95% of the trace elements retained. In procedure III the matrix was separated by its precipitation as ZrOCl₂·8 H₂O from a (1:4) HCl-acetone medium. More than 98% of Zr were removed and more than 90% of the trace elements were retained. In procedure IV the ZrO₂ powder was dispersed by ultrasonic treatment in water acidified with HCl (pH 2) and the slurry was directly analyzed by ICP-AES using a Babington nebulizer. The optimization and the analytical features of this procedure will be described in a subsequent paper. In all procedures the calibration was performed by standard addition and matrix matching was not necessary. The detection limits varied from 0.3 g/g (Ca) to 10 g/g (Al). The standard deviations obtained were 1–10% depending on the element and its concentration in the sample. The results of the procedures for 6 commercially available fine ZrO₂ powders were found to agree for Al, Ca, Fe, Mg, Na, Ti and Y. A good agreement between the results of the procedures using matrix separation was also observed for Cu, Mn, V, but the concentrations of these elements found by methods without matrix separation were considerably higher. Except for Ca and Mg the blank values encountered were below the detection limits.On leave from Department of Analytical Chemistry, Technical University, PL-00-664 Warsaw, Poland     

Determination of Nb and Ta in Nb/Ta minerals by inductively coupled plasmas optical emission spectrometry using slurry sample introduction

The determination of Nb and Ta in Nb–Ta minerals was accomplished by slurry nebulization inductively coupled plasma optical emission spectrometry (ICP-OES), using a clog-free V-groove ceramic nebulizer. Samples were first wet-ground to appropriate particle sizes with narrow size distribution and 90% of the particles in the slurry were smaller than 2.32 μm in diameter. Subsamples were then dispersed in pH 9 aqueous solutions, and agitated in an ultrasonic bath for 15 min prior to analysis. Due to the lack of slurry standards matching well with the samples, calibration was simply carried out using aqueous solution standards. Results were compared with those obtained from a conventional fusion decomposition procedure and acid digestion procedures and a good agreement between the measured and referred values was obtained. The technique provided a good alternative for the rapid determination of Nb and/or Ta in their corresponding minerals.     

Comparative determination of Ba, Cu, Fe, Pb and Zn in tea leaves by slurry sampling electrothermal atomic absorption and liquid sampling inductively coupled plasma atomic emission spectrometry

The comparative determination of barium, copper, iron, lead and zinc in tea leaf samples by two atomic spectrometric techniques is reported. At first, slurry sampling electrothermal atomization atomic absorption spectrometry (ETAAS) was applied. The results of Ba and Pb determination were calculated using the method of standard additions, and results of Cu, Fe and Zn from the calibration graphs based on aqueous standards. These results were compared with the results obtained after microwave-assisted wet (nitric+hydrochloric+hydrofluoric acids) digestion in closed vessels followed by inductively coupled plasma-atomic emission spectrometric (ICP-AES) determination with the calibration by means of aqueous standards. The exception was lead determined after a wet digestion procedure by ETAAS. The accuracy of the studied methods was checked by the use of the certified reference material Tea GBW-07605. The recoveries of the analytes varied in the range from 91 to 99% for slurry sampling ETAAS, and from 92.5 to 102% for liquid sampling ICP-AES. The advantages of slurry sampling ETAAS method are simplicity of sample preparation and very good sensitivity. Slurry sampling ETAAS method is relatively fast but if several elements must be determined in one sample, the time of the whole microwave-assisted digestion procedure and ICP-AES determination will be shorter. However, worse detection limits of ICP-AES must also be taken into the consideration in a case of some analytes.     

Determination of cadmium in polyethylene by analytical atomic spectrometry with gas-phase sample introduction technique

Cadmium in polyethylene was determined by both inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrometry (AAS) with continuous-flow gas-phase sample introduction in a reaction medium of ascorbic acid. In the presence of mixture of cobalt and thiourea in the ascorbic acid solution, the sensitivities by both ICP-AES and AAS for cadmium were greatly enhanced. The gaseous cadmium species was phase-separated in a gas–liquid separator and directed via a stream of argon carrier gas to an inductively coupled plasma and an electrically heated quartz tube atomizer (QTA) for atomic spectrometry. Under the optimized experimental conditions, the best attainable detection limits at Cd I 228.802 nm line were 1.3 and 0.017 ng/ml with linear dynamic ranges of 10–500 ng/ml and 0.1–1 ng/ml in concentrations by ICP-AES and QTA-AAS, respectively. The instrumental precisions expressed as the relative standard deviation (R.S.D.) from ten replicate measurements of 50 and 1 ng/ml cadmium by ICP-AES and QTA-AAS were 5.6% and 3.2%, respectively. With the use of ICP-AES and QTA-AAS with gas-phase sample introduction method, six- and 200-fold improvements in detection limits for cadmium were obtained in comparison with their conventional solution nebulization methods, respectively. After the effects of several diverse elements on the determination of cadmium by ICP-AES and QTA-AAS with the present gas-phase sample introduction systems were examined, these methods were applied to the determination of low concentrations of cadmium in polyethylene. The results obtained by the present method were in good agreement with the certified values.     

Direct determination of impurities in high purity silicon carbide by inductively coupled plasma optical emission spectrometry using slurry nebulization technique

A novel method for the determination of Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni and Ti in high purity silicon carbide (SiC) using slurry introduction axial viewed inductively coupled plasma optical emission spectrometry (ICP-OES) was described. The various sizes of SiC slurry were dispersed by adding dispersant polyethylene imine (PEI). The stability of slurry was characterized by zeta potential measurement, SEM observation and signal stability testing. The optimal concentration of PEI was found to be 0.5 wt% for the SiC slurry. Analytical results of sub-μm size SiC by the slurry introduction were in good accordance with those by the alkaline fusion method which verified that determination could be calibrated by aqueous standards. For μm size SiC, results of most elements have a negative deviation and should be calibrated by the Certified Reference Material slurry. Owing to a rather low contamination in the sample preparation and stability of the slurry, the limits of detection (LODs), which are in the range of 40-2000 ng g⁻¹, superior to those of the conventional nebulization technique by ICP-OES or ICP-MS.     

Determination of arsenic in fly ash by hydride generation in a slurry

We have studied the generation of arsenic hydride on a fly ash slurry from a thermal power plant burning lignite. The conditions for the formation of the slurry were optimized and the influence of the presence of various surfactants on the formation and stability of slurry (particle size-analytical signal ratio) were investigated.The As content in the ash was 78.7 g/g, with an rsd of 5.6% and a detection limit of 2.8 ng. The proposed method was successfully applied to the determination of arsenic in a certified ash sample (BCR-38). This method was applied to fly ash from a thermal power plant burning anthracite.     

Comparison of pneumatic and ultrasonic nebulizations in inductively coupled plasma atomic emission spectrometry — matrix effects and plasma parameters

Matrix effects and plasma parameters in inductively coupled plasma atomic emission spectrometry (ICP-AES) using the sample introduction systems with ultrasonic and pneumatic nebulizations were studied. Analytical line intensities of fourteen elements and their detection limits as well as plasma temperatures, electron number density and ion-to-atom line intensity ratios were investigated with and without presence of complex matrix composed of Na, K, Mg and Ca. With ultrasonic nebulization in comparison to pneumatic nebulization, the line intensities were enhanced and the enhancement factor was dependent on the total line excitation energy. For each type of the sample introduction system, the changes in line intensities induced by the complex matrix were correlated with the sum of Ca and Mg concentrations. The excitation temperatures of atoms and ions, the ionization temperatures and the ion-to-atom line intensity ratios were the lowest using the ultrasonic nebulizer and quite well comparable for both pneumatic nebulizers (Meinhard and V-groove). The differences between excitation temperatures of ions and atoms were the largest while the electron number density was the lowest when the ultrasonic nebulizer was employed. Generally, the plasma parameters were independent of the matrix composition. The differences in plasma parameters observed for the individual nebulizers were related to various amounts of solvent loaded to the plasma.     

The determination of phosphonate base scale inhibitors in brines by plasma spectrometry

The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.