Multi-elemental analysis of non-food packaging materials by inductively coupled plasma-time of flight-mass spectrometry

Commercial non-food packaging materials of four different matrices (paper, low density polyethylene (LDPE), polyethylene-polypropylene (PE-PP) and high density polyethylene (HDPE)) were examined for the content of Cr, Ni, Cu, Zn, As, Mo, Cd, Sb, Ba, Hg, Tl, Pb and U. The examined samples (0.17–0.35 g) were digested in HNO₃ and H₂O₂ (papers, LDPE and PE-PP) and in HNO₃, H₂SO₄ and H₂O₂ (HDPE) using microwave assisted high pressure system. The inductively coupled plasma-time of flight-mass spectrometry (ICP-TOFMS) has been employed as the detection technique. All measurements were carried out using internal standardization. Yttrium and rhodium (50 ng g⁻¹) were used as internal standards. The detection and quantification limits obtained were in the range of 0.005 ng g⁻¹ (⁵²Cr) to 0.51 ng g⁻¹ (⁶⁶Zn) and 0.015 μg g⁻¹ (⁵²Cr) to 2.02 μg g⁻¹ (⁶⁶Zn) of dry mass, respectively. The evaluated contents (mg kg⁻¹) of particular elements in the examined materials were as follows: 0.22–219; <1.05–9.03; 1.25–112; <2.02–449; <0.98–<1.30; <0.36–2.06; <0.29–113; <0.22–44.1; <0.06–57.4; <0.66–<0.88; <0.08–0.24; <0.13–1222 and <0.08–0.44 for Cr, Ni, Cu, Zn, As, Mo, Cd, Sb, Ba, Hg, Tl, Pb and U, respectively.     

银菊珍珠胶囊中稀土元素的电感耦合等离子体质谱分析

建立了一种电感耦合等离子体质谱法测定银菊珍珠胶囊中稀土元素的方法。利用该方法分析了国家一级灌木枝叶标准物质（GBW 07603）和国际柑橘叶标准物质（NIST1572）中的稀土元素,结果与标准值一致。该方法已被用于分析银菊珍珠肢囊样品中的稀土元素。     

Comparison of inductively coupled plasma spectrometry techniques for the direct determination of rare earth elements in digests from geological samples

Inductively coupled plasma quadrupole mass spectrometry (ICP-QMS), ICP sector field mass spectrometry (ICP-SFMS) and ICP atomic emission spectrometry (ICP-AES) were compared with regard to the direct determination of rare earth elements (REEs) in geological samples. In order to reduce the polyatomic interferences occurring in ICP-QMS, the use of a cooled spray chamber was optimized, obtaining a significant decrease of the oxide ions formation (about 50%) and a consequent mitigation of the interfering effects. Precision and accuracy of the method were demonstrated by the analyses of sediment and soil certified reference materials. ICP-SFMS working in high-resolution mode also provided accurate results, with similar precision to ICP-QMS (RSD%: 3-8%) and comparable or better limits of detection. Quantification limits of the procedures were 18-52 ng g⁻¹ and 10-780 ng g⁻¹ for sector field- and quadrupole-ICP-MS, respectively. Accurate and precise determination of most REEs was also achieved by ICP-AES using both pneumatic and ultrasonic nebulization, after a careful selection of the emission lines and compensation for non-spectral interferences by internal standardization. The three techniques were finally applied to glaciomarine sediment samples collected in Antarctica, providing comparable analytical data on REE abundance and depth pattern.     

Trace elements content in size-classified volcanic ashes as determined by inductively coupled plasma-mass spectrometry

At present there is an increasing concern as regards the release of potentially toxic metals into the environment. Volcanic eruptions are a natural source of metals and metalloids in the atmosphere. Toxic trace elements ejected during an eruptive episode may produce hazardous effects for people and the environment in areas close to the volcano. In this context, a study was undertaken to investigate the concentration of metal and metalloids in ashes ejected from Copahue volcano, Neuquén, Argentina. Two samples (A and B) of deposited particles were collected one day after the first eruption and size-fractionated in four sub-samples (S1, S2, S3 and S4). Analysis was performed by inductively coupled plasma-mass spectrometry (ICP-MS) and the accuracy for the entire analytical procedure was performed by means of the certified reference material CRM GBW 07105 Rocks (NRCCRM, China). The elements considered were: As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, U, V and Zn. The adverse effect of potentially interfering species on the mass-spectrometric determination of these elements was also taken into account. The concentration intervals found in the four fractions are as follows (in μg g⁻¹): As, 6.0-2.6; Cd, 0.71-0.36; Cr, 29.5-54.0; Cu, 132-49.0; Hg, 0.020-0.007; Ni, 36.0-26.0; Pb, 15.5-2.55; Sb, 1.07-0.30; U, 2.57-1.94; V, 152-106; Zn, 85.5-55.0. The elements with the highest concentrations were: Cu, V and Zn. All fractions, in both samples, were found to be enriched in some toxic trace elements in the following order Sb>Cd>As. On the contrary, samples were depleted in Ni, Cr and Hg. Lead was the element that exhibits a noticeable difference in concentration between the finer and coarser fractions.     

On-line preconcentration with a novel alkyl phosphinic acid extraction resin coupled with inductively coupled plasma mass spectrometry for determination of trace rare earth elements in seawater

A newly synthesized alkyl phosphinic acid resin (APAR) was used for on-line preconcentration of trace rare earth elements (REES, lanthanides including yttrium) and then determined by inductively coupled plasma mass spectrometry. REEs in seawater could be on-line concentrated on the APAR packed column (4.6 mm i.d. × 50 mm in length), and eluted from the column with 0.5 mL 0.1 mol L⁻¹ nitric acid within 30 s. An enrichment factor of nearly 400 was achieved for all REEs when the seawater sample volume was 200 mL, while the matrix and coexisting spectrally interfering ions such as barium, tin and antimony could be simultaneously separated. The detection limits of this proposed method for REEs were in the range from 1.43 pg L⁻¹ of holmium to 12.7 pg L⁻¹ of lanthanum. The recoveries of REEs were higher than 97.9%, and the precision of the relative standard deviation (R.S.D., n = 6) was less than 5%. The method has been applied to the determination of soluble REEs in seawater.     

Preconcentration and atomic spectrometric determination of rare earth elements (REEs) in natural water samples by inductively coupled plasma atomic emission spectrometry

The usage of a variety of sorbents has been shown as promising matrix removal/preconcentration strategies for the determination of rare earth elements (REEs) in various natural water samples by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sorption efficiency of various zeolites (clinoptilolite, mordenite, zeolite Y, zeolite Beta), ion-exchangers (Amberlite CG-120, Amberlite IR-120, Rexyn 101, Dowex 50W X18) and chelating resins (Muromac, Chelex 100, Amberlite IRC-718) towards REEs was investigated in terms of solution pH, shaking time and sorbent amount. The results have shown that most of the materials can take up REEs at a wide pH range. The experiments were continued with clinoptilolite, zeolite Y and Chelex 100 and it was demonstrated that all three materials displayed very fast kinetics for REE sorption (higher than 96% in 1 min). Desorption from the sorbents was realized with 2.0 M HNO₃ for clinoptilolite and 0.1 M HNO₃ for zeolite Y and Chelex 100. Only the lower concentration range (0.01-2.0 mg l⁻¹) of matrix-matched standards were used in quantitation although the calibration graphs were linear at least up to 10.0 mg l⁻¹ for all REEs studied. The limit of detection (3 s) without preconcentration was 0.1, 1.0, and 0.2 μg l⁻¹ for Eu, La, and Yb, respectively. The validity of the method with the selected sorbents was checked through spike recovery experiments.     

A magnesium hydroxide preconcentration/matrix reduction method for the analysis of rare earth elements in water samples using laser ablation inductively coupled plasma mass spectrometry

This paper describes a simple method for simultaneous preconcentration and matrix reduction during the analysis of rare earth elements (REEs) in water samples through laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). From a systematic investigation of the co-precipitation of REEs using magnesium hydroxide, we optimized the effects of several parameters - the pH, the amount of magnesium, the shaking time, the efficiency of Ba removal, and the sample matrix - to ensure quantitative recoveries. We employed repetitive laser ablation to remove the dried-droplet samples from the filter medium and introduce them into the ICP-MS system for determinations of REEs. The enrichment factors ranged from 8 to 88. The detection limit, at an enrichment factor of 32, ranged from 0.03 to 0.20 pg mL⁻¹. The relative standard deviations for the determination of REEs at a concentration of 1 ng mL⁻¹ when processing 40 mL sample solution were 2.0-4.8%. We applied this method to the satisfactory determination of REEs in lake water and synthetic seawater samples.     

Uncertainty propagation through correction methodology for the determination of rare earth elements by quadrupole based inductively coupled plasma mass spectrometry

Determination of rare earth elements by quadrupole based inductively coupled plasma mass spectrometry (ICP-QMS) shows several spectroscopic overlaps from M⁺, MO⁺ and MOH⁺ ions. Especially, the spectroscopic interferences are observed from the atomic and molecular species of lighter rare earth elements including Ba during the determination of Eu, Gd and Tb. Mathematical correction methods, knowing the at.% abundances of different interfering isotopes, and the extent of formation of molecular species determined experimentally, have been used to account for various spectroscopic interferences. However, the uncertainty propagated through the mathematical correction limits its applicability. The uncertainty propagation increases with the increase in contribution from interfering species. However, for the same extent of total contribution, the overall error decreases when the interfering species are more than one. In this work, chondrite as well as a few geological reference materials containing different proportions of various rare earth elements have been used to study the contributions of different interfering species and the corresponding uncertainty in determining the concentrations of rare earth elements. A number of high abundant isotopes are proposed for determining the concentrations of various rare earth elements. The proposed isotopes are tested experimentally for determining the concentrations of different rare earth elements in two USGS reference materials AGV-1 and G-2. The interferences over those isotopes are corrected mathematically and the uncertainties propagated due to correction methodology are determined for those isotopes. The uncertainties in the determined concentrations of rare earth elements due to interference correction using the proposed isotopes are found to be comparable with those obtained by the commonly used isotopes for various rare earth elements.     

ICP-AES 法测定硅铁中痕量元素

采用电感耦合等离子原子发射光谱法测定硅铁中的痕量元素,研究了 Fe 基体对被测元素的影响,并选择了最佳工作条件.被测元素的检测限为 0 .60～76.2 ng/mL,样品加标回收率为 92%～108%,RSD(n=8)<3%.     

On-line preconcentration of some rare earth elements in water samples using C18-cartridge modified with l-(2-pyridylazo) 2-naphtol (PAN) prior to simultaneous determination by inductively coupled plasma optical emission spectrometry (ICP–OES)

The on-line column preconcentration technique with inductively coupled plasma optical emission spectroscopy (ICP–OES) has been developed using a cartridge filled with octadecyl silica modified by l-(2-pyridylazo) 2-naphtol (PAN). The aim of this method was to determine some rare earth elements (REEs) (Ce, Dy, La, Sm, and Y) and uranium in water samples. Sample solutions were passed through the C₁₈-modified column. The adsorbed cations were subsequently eluted from the column and transferred into the plasma with nitric acid solution for simultaneous determination of them. Sample pH, amount of PAN as a complexing agent, sampling and eluting flowrates and concentration of the eluent were optimized. Detection limits based on three times of standard deviations of blank by 10 replicates were in the range of 11 ng l⁻¹ for Dy to 69 ng l⁻¹ for U. Sample throughput was 10 samples h⁻¹. The proposed method was applied to determine REEs in natural water samples. Recoveries of the REEs from natural water samples were between 95 and 106% with percent relative standard deviation (%R.S.D.) of 1.0–7.9%.     

珍珠中痕量稀土元素的ICP-MS测定及其分布特性

探讨了等离子体质谱(ICP-MS)分析珍珠样品中稀土元素的基体效应及多原子离子干扰,并采用干扰校正因子进行有效的校正,以In-Rh双内标校正体系进行分析信号动态漂移的监控和补偿,建立了珍珠样品中稀土元素的ICP-MS分析方法。方法的定量检出限为0．1～0．5ng／g,RSD≤15％(n=5)。所建立的方法用于标准物质Gui-1、Gui-2、Gui-3及人工养殖珍珠的分析。珍珠中稀土元素的分布与分馏特性与其生长环境密切相关。     

微波消解-电感耦合等离子体质谱法(ICP-MS)测定板栗中的矿物元素及稀土元素[ ]

采用微波消解前处理方法,结合电感耦合等离子体质谱技术,建立了板栗中钠（Na）、钾（K）、镁（Mg）、锰（Mn）、铁（Fe）、钒（V）、钴（Co）等19种矿物元素及镧（La）、铈（Ce）、镨（Pr）、钕（Nd）、钐（Sm）、铕（Eu）、钆（Gd）、铽（Tb）、镝（Dy）、钬（Ho）、铒（Er）、铥（Tm）、镱（Yb）、镥（Lu）、钇（Y）等15种稀土元素的同时分析测定方法。该方法检出限为0.0027~0.78μg?L-1,相对标准偏差为1.4%~6.3%。通过国家标准物质GBW10019苹果的准确率实验验证,测定结果均在标准证书值范围内。实验结果表明,该方法适用于板栗中矿物元素及稀土元素的同时测定。     

电感耦合等离子体质谱法测定三水铝土矿中的15种有效稀土元素

建立电感耦合等离子体质谱法测定三水铝土矿中15种有效稀土元素的分析方法。参考三水铝土矿中有效铝的概念,提出了有效稀土元素的概念,并对三水铝土矿中稀土元素的回收利用的可行性进行了评价。模拟低温拜耳法生产氧化铝的工艺,对三水铝土矿中稀土元素溶出过程中的氢氧化钠浓度、溶出温度及时间等条件进行了试验,采用90 g/L氢氧化钠结合微波消解技术对三水铝土矿进行分解,用ICP-MS法测定有效稀土元素,有效稀土元素测定结果的相对标准偏差为0.92%~7.40%(n=7),回收率为98.6%~101.2%。该方法可用于测定三水铝土矿中有效稀土元素,能够对三水铝土矿中稀土元素的回收利用价值进行评价。     

Comparison of microconcentric and membrane-desolvation sample introduction systems for determination of low rare earth element concentrations in surface and subsurface waters using sector field inductively coupled plasma mass spectrometry

Analytical performances of a microconcentric nebulizer (MCN) and a membrane-desolvation sample introduction system (Aridus) were compared for determination of low concentrations of rare earth elements (REEs) in surface and subsurface waters using a double focusing sector field inductively coupled plasma mass spectrometer. Conventional figures of merit were employed, such as sensitivities, limits of detection (LOD), REE–O⁺ formation, matrix induced interferences, long term signal variations, and recovery from spiked sea water samples and a pristine water CRM.     

Determination of trace elements in natural waters by inductively coupled plasma time of flight mass spectrometry after flow injection preconcentration in a knotted reactor

A flow injection on-line sorption system was developed for the separation and preconcentration of traces of Ag, Cd, Co, Ni, Pb, U and Y from natural water samples with subsequent detection by ICP TOF MS. Simultaneous preconcentration of the analytes was achieved by complexation with the chelating reagent 1-phenyl-3-methyl-4-benzoylpyrazol-5-one immobilized on the inner walls of a (200 cm × 0.5 mm) PTFE knotted reactor. The analytes were eluted and transported to an axial ICP TOF MS system with 1% (v/v) HNO₃ containing 0.3 μg l⁻¹ of Rh as an internal standard using ultrasonic nebulization. The detection limits (3σ) varied from 0.3 ng l⁻¹ for Y to 15.2 ng l⁻¹ for Ni and the precision (R.S.D.) was better than 4%. Using a loading time of 90 s and a sample flow rate of 4.5 ml min⁻¹, enhancement factors of 3-14 were obtained for the different analytes in comparison with their direct determination by ICP TOF MS with ultrasonic nebulization without preconcentration. The accuracy of the method was demonstrated by analysis of water based certified reference materials.     

Polymer monolithic capillary microextraction combined on‐line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples

A rapid and sensitive method based on polymer monolithic capillary microextraction combined on‐line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate‐trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h^?1, and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82–105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume.     

Direct determination of rare earth impurities in high purity erbium oxide dissolved in nitric acid by inductively coupled plasma mass spectrometry

A novel method was developed for the direct determination of trace quantities of rare earth elements (REEs) in high purity erbium oxide dissolved in nitric acid by inductively coupled plasma mass spectrometry (ICP-MS) in this work. The mass spectra overlap interferences arose from Er matrix on the neighbouring and monoisotopic analytes of ¹⁶⁵Ho(100) and ¹⁶⁹Tm(100) were eliminated by adjusting instrumental peak resolution value from 0.7 to 0.3 amu. The matrix suppression effect of Er on the ion peak signals of REEs impurities was effectively compensated with spiking In as internal standard element. The limit of quantitation (LOQ) of REEs impurities was from 0.0090 to 0.025 μg g⁻¹, the recoveries of spiked sample for REEs were found to be in the range of 90.3-107% through using the proposed method and relative standard deviation (R.S.D.) varied between 2.5% and 6.7%. The novel methodology had been found to be suitable for the direct determination of trace REEs impurities in 99.999-99.9999% high purity Er₂O₃ and the results obtained from this method keep in good agreement with that acquired from high resolution ICP-MS.     

Solid phase extraction for analysis of biogenic carbonates by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS): an investigation of rare earth element signatures in otolith microchemistry

Uptake of trace elements into fish otoliths is governed by several factors such as life histories and environment in addition to stock and species differences. In an attempt to elucidate the elemental signatures of rare earth elements (REEs) in otoliths, a solid phase extraction (SPE) protocol was used in combination with electrothermal vaporization (ETV) as a sample introduction procedure for the determinations by inductively coupled plasma quadrupole mass spectrometry (ICP-MS). Effects of various parameters, such as carrier gas flow rate, atomization temperature and chemical modification, were examined for optimization of the conditions by ETV-ICP-MS. Atomization was achieved at 2800 °C. Lower temperatures (i.e. 2600 °C) resulted in severe memory problems due to incomplete atomization. Palladium was used as a chemical modifier. It was found that an increase in Pd concentration up to 0.5 μg in the injection volume (70 μl) led up to four-fold enhancement in the integrated signals. This phenomenon is attributed to the carrier effect of Pd rather than the stabilization since no significant losses were observed for high temperature drying around 700 °C even in the absence of Pd. Preconcentration was performed on-line at pH 5 by using a mini-column of Toyopearl AF-Chelate 650M chelating resin, which also eliminated the calcium matrix of otolith solutions. After preconcentration of 6.4 ml of solution, the concentrate was collected in 0.65 ml of 0.5% (v/v) HNO₃ in autosampler cups, and then analyzed by ETV-ICP-MS. The method was validated with the analysis of a fish otolith certified reference material (CRM) of emperor snapper, and then applied to samples. Results obtained from otoliths of fish captured in the same habitat indicated that otolith rare earth element concentrations are more dependent on environmental conditions of the habitat than on species differences.     

Application of ultrasound-assisted acid leaching procedures for major and trace elements determination in edible seaweed by inductively coupled plasma-optical emission spectrometry

A new method using diluted reagents (nitric and hydrochloric acids and oxygen peroxide) and ultrasound energy to assist metals acid leaching with from edible seaweed was optimized. The method uses a first sonication at high temperature with hydrochloric acid as a previous stage to an ultrasound-assisted acid leaching with 7 ml of an acid solution containing nitric acid, hydrochloric acid and hydrogen peroxide at concentrations of 3.7, 3.0 and 3.0 M, respectively. Optimum conditions for the first sonication step were ultrasound energy at 17 kHz, sonication temperature at 65 °C, an acid volume of 2 ml, an hydrochloric acid concentration of 6.0 M and a sonication time of 10 min. It has been found that the first sonication stage at high temperature with hydrochloric acid is necessary to obtain quantitative recoveries for As, Ba, Fe and V. Otherwise quantitative recoveries were reached for the other elements investigated (Ca, K, Na, Mg, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The repeatability of the ultrasound-assisted acid leaching method was around 10% for all elements. Adequate limit of detection and limit of quantification were reached by using inductively coupled plasma-optical emission spectrometry (ICP-OES) for measurements. The method resulted accurate after analysing several seaweed certified reference materials (IAEA-140/TM, NIES-03 and NIES-09). The method was finally applied to the multi-element determination in edible seaweed samples.     

电感耦合等离子体质谱(ICP-MS)法测定金绿宝石中16种痕量稀土元素

金绿宝石结构稳定,常规敞开酸溶、密闭酸溶、微波消解三种前处理方法并不能将其完全分解,测定结果偏低。本文采用碳酸钠-硼酸混合熔剂进行熔融,样品分解完全,建立了电感耦合等离子体质谱法(ICP-MS)测定金绿宝石中16种痕量稀土元素的分析方法。选择丰度高、干扰小的同位素、动能歧视碰撞池(KED)模式及干扰系数校正法消除质谱干扰,以185Re为内标元素及样品稀释降低基体干扰。实验表明：各稀土元素的校准曲线相关系数r值在0.9991~0.9998之间,方法检出限为0.0001~0.0134 μg/g,定量限为0.0005~0.0670 μg/g。采用国家标准物质GBW07151验证方法的精密度,计算出相对标准偏差(RSD, n=7)在1.3%~4.6%之间,并将此方法用于金绿宝石实际样品中稀土元素的测定,RSD为0.9%~3.2%,加标回收率为94%~104%,符合国家地质矿产行业标准,结果稳定、可靠。