Direct determination of methylmercury and inorganic mercury in biological materials by solid sampling-electrothermal vaporization-inductively coupled plasma-isotope dilution-mass spectrometry

This paper reports on the use of solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry (SS-EIV-ICPMS) for the direct and simultaneous determination of methylmercury and inorganic mercury in biological materials. The main advantage of this fast and sensitive method is that no sample preparation is required. In this way, the sample throughput can be considerably increased, problems of contamination and analyte losses are kept to a minimum and, even more important, the original chemical form of the different analyte species in the solid samples is preserved. To achieve this goal, a solid sample is inserted into a graphite furnace of the boat-in-tube type and is subsequently submitted to an appropriate temperature program, leading to the separate vaporization of methylmercury and inorganic mercury, which are transported into the ICP by means of an argon carrier gas. The separation was accomplished within 75 s. For the quantification of the two peaks, species-unspecific isotope dilution was used. For this purpose, a stable flow of argon loaded with gaseous Hg isotopically enriched in 200Hg was generated using a permeation tube that was constructed in-house. Its emission rate was determined by collecting the mercury released during a given time interval on a gold-coated silica absorber, after which the amount collected was released by heating of the absorber and determined by cold vapor atomic absorption spectrometry (CVAAS) and cold vapor atomic fluorescence spectrometry (CVAFS). A reference material from the Canadian National Research Council (NRC) (TORT-2) was used to assess the accuracy of the method. For the application of the method to samples with diverse mercury contents, the spike/sample ratio can be optimized by varying the emission rate of the permeation tube simply by adapting its temperature. To prove the feasibility of this approach, two reference materials (BCR 463 and DORM-2) with a methylmercury content more than 10 times higher than that of TORT-2 were also analyzed. The detection limits obtained for 1 mg of sample (2 ng g(-1) and 6 ng g(-1) for methylmercury and inorganic mercury, respectively) were found to be sufficiently low for this kind of application and are competitive when compared to other techniques.     

Determination of phytic acid in urine by inductively coupled plasma mass spectrometry

An ICPMS method for the determination of phytic acid in human urine based on the total phosphorus measurement of purified extracts of phytic acid is described. Pretreatment of the sample is required to avoid interference in the ICPMS detection from other phosphorus compounds accompanying phytic acid in urine such as phosphate or pyrophosphate. This treatment consists of a simple filtration of the urine sample followed by complete separation of phytic acid from the mentioned phosphorus components using an anion-exchange solid-phase extraction. Separation/recovery conditions, optimized for standards of phytic acid prepared in water and artificial urine, were successfully applied to natural urine samples, resulting in adequate accuracy and precision. Linear range (0.02-0.6 mg of phytic acid L(-)(1)) and limit of detection (5 microg L(-)(1) phytic acid) are adequate for analysis of the usual amounts of phytic acid present in urine. Phosphate, pyrophosphate, and pH of urine samples at concentrations exceeding their normal physiological ranges do not affect the determination of phytic acid. Because of the simplicity, low sample requirement, and relatively high sample throughput (10 to 6 min per sample for runs between 50 and 100 samples, respectively), the present method presents the best alternative to current methods for phytic acid determination in urine. Results also show that the method is adequate for the differentiation of levels of phytic acid excretion from patients suffering from oxalocalcic urolithiasis and healthy controls, suggesting that low phytic acid concentrations in urine lead to elevated risk of oxalocalcic urolithiasis.     

Determination of thorium and uranium in ultrapure lead by inductively coupled plasma mass spectrometry

A method for the determination of U and Th at sub-ppt levels in high-purity Pb samples using extraction chromatography with ICPMS detection is described. Following acid digestion, uranium and thorium are separated from the lead matrix using UTEVA resin. Sorption and elution procedures were optimized, the potential reusability of the chromatographic resin was evaluated, and a performance comparison between prepacked and freshly prepared UTEVA column was made. Uranium could be eluted with 0.025 M HCl and Th then recovered using 0.5% oxalic acid. Recovery yields for U exceed 80% whereas those for Th were typically 60%. Procedural detection limits of 0.5 and 1.5 pg g(-)(1) were obtained for U and Th, respectively. For purposes of comparison, GD-MS analysis of samples was also performed, yielding results consistent with those generated by ICPMS but with inferior detection power.     

Determination of methylmercury in environmental matrixes by on-line flow injection and atomic fluorescence spectrometry

The precision and bias of monomethylmercury (MMHg) determinations in environmental samples can be improved by directly coupling and automating the numerous steps involved with analysis of this toxic Hg species. We developed a simple and robust mercury speciation analyzer (MSA) for measurement of MMHg in environmental matrixes. This on-line hyphenated system couples the main analytical steps, including sample introduction, aqueous-phase ethylation, Tenax preconcentration, and gas chromatographic separation, to cold vapor atomic fluorescence detection and data acquisition. Here we describe the MMHg-MSA, present results of laboratory optimization and performance tests, and compare the reproducibility between dual analytical channels. With alternating sample concentration and analysis, a dual-channel system permits six high-accuracy MMHg determinations per hour. Additional advantages compared to the traditional manual method include ease of operation and high precision (<5% relative standard deviation). The MSA is applicable to the determination of MMHg in various environmental matrixes, and it can be fully automated. This method was validated by analysis of MMHg in certified reference materials of sediment and biological tissue. Estimated detection limits for MMHg with the MSA are approximately 0.01 ng g(-1) for a 0.1-g sample of dry sediment or fish and approximately 0.01 ng L(-1) for 0.15 L of water.     

Water analysis by inductively coupled plasma mass spectrometry

The major problems in the analysis of various natural and potable waters by the method of inductively coupled plasma mass spectrometry (sampling, matrix effects, and spectral interferences) are studied; recommendations for addressing them are given. New data on the use of robust conditions for spectrometer settings to increase its tolerance to matrix effects are considered. The advantages of combination of mass spectrometry with the simpler atomic emission method, which allows expanding the range of determined elements and increasing the reliability of the analysis, are discussed.     

Pharmacokinetic investigation on a novel antitumour platinum compound in rabbit plasma by inductively coupled plasma mass spectrometry after intravenous administration

The purpose of this study was to investigate a novel platinum anticancer compound named as SM54111 [cis-3, 5-diisopropylsalylic cyclohexanodiaminoplatinum (II)], which is under development as a new drug candidate, on its pharmacokinetics in plasma after intravenous administration to rabbits at concentration of 2.5, 5.0, and 9.0 mg/kg. The concentration of SM54111 in plasma expressed as Pt was determined utilizing ICP-MS method, and the method was thoroughly validated. The data were analyzed with 3P97 pharmacokinetic software to find the parameters. The results showed that the linear range lay at the 1 approximately 1000 ng/mL level, and the LOD and LOQ were 0.4 ng/mL and 1 ng/mL, respectively. It proved that this new drug candidate underwent disposition in rabbit plasma by a two-compartment open model at the three doses above, and the main pharmacokinetic parameters were obtained as the initial concentrations of three doses (C(0)) were 8.68 +/- 0.80, 20.04 +/- 1.92, and 28.88 +/- 2.32 mg/L, respectively; the areas under concentration-time profile from time 0 to 72 h (AUC(0 approximately t)) were 90.0 +/- 13.0, 251.3 +/- 45.3, and 396.9 +/- 61.1 mg*h/L, respectively; the terminal elimination half-life times (t(1/2beta)) 29.1 +/- 4.8, 35.2 +/- 7.5, and 29.4 +/- 2.8 h, respectively; and the total clearances (CL(tot)) were 0.026 +/- 0.004, 0.019 +/- 0.002, and 0.022 +/- 0.004 L/h, respectively. First order rate pharmacokinetics were observed for SM54111 with the doses used, and it showed a long retention and slow elimination in vivo, There showed no prolongation of the t(1/2beta) with larger dose, and the CLs of the three doses were proximate. It is reasonable to surmise that SM54111 follows first order rate pharmacokinetics, and no saturation was detected at concentrations from 2.5 to 9.0 mg/kg. This result suggested that SM54111 experienced an amiable procedure in vivo and was worthy of the further development.     

Determination of mercury in coal by isotope dilution cold-vapor generation inductively coupled plasma mass spectrometry

A method based on isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has been developed for high-accuracy determinations of mercury in bituminous and sub-bituminous coals. A closed-system digestion process employing a Carius tube is used to completely oxidize the coal matrix and chemically equilibrate the mercury in the sample with a 201Hg isotopic spike. The digestates are diluted with high-purity quartz-distilled water, and the mercury is released as a vapor by reduction with tin(II) chloride. Measurements of 201Hg/202Hg isotope ratios are made using a quadrupole ICPMS system in time-resolved analysis mode. The new method has some significant advantages over existing methods. The instrument detection limit is less than 1 pg/mL. The average blank (n = 17) is 30 pg, which is roughly 1 order of magnitude lower than the equivalent microwave digestion procedure. The detection limit in coal is blank limited and is approximately 40 pg/g. Memory effects are very low. The relative reproducibility of the analytical measurements is approximately 0.5% for mercury concentrations in the range 10-150 ng/g. The method has been used to measure mercury concentrations in six coal reference materials, SRM 1632b (77.4 ng/g), SRM 1632c (94.3 ng/g), BCR 40 (433.2 ng/g), BCR 180 (125.0 ng/g), BCR 181 (135.8 ng/g), and SARM 20 (252.6 ng/g), as well as a coal fly ash, SRM 1633b (143.1 ng/g). The method is equally applicable to other types of fossil fuels including both crude and refined oils.     

Determination of macroconcentrations of platinum by combined application of gravimetry and inductively coupled plasma—Atomic emission spectrometry

A combined method for macroconcentrations of platinum determination in chloroplatinic acid and industrial concentrate obtained during processing of some types of electronic engineering scrap that is based on a combination of gravimetric precipitation of platinum by ammonium chloride with subsequent determination of a residual concentration of platinum in a filtrate using the ISP-AES method is developed. The errors at each stage of analysis, as well as the total error, are estimated. It is shown that the accuracy of macro-concentrations of platinum determination using the combined method is not inferior to the accuracy of classical gravimetric analysis (the relative standard deviation does not exceed 0.15% for 15–40% wt concentrations of platinum). The combined method of analysis based on a combination of gravimetry and ISP-AES makes it possible to decrease labor expenditures and the time of analysis as compared to the classical one.     

Determination of phosphorous and sulfur in environmental samples by electrothermal vaporization inductively coupled plasma atomic emission spectrometry

From the viewpoint of selective introduction of the analyte from its solvent and matrices, electrothermal vaporization (ETV) is useful for the sample introduction into the inductively coupled plasma (ICP). By using a tungsten boat furnace (TBF) vaporizer system, the loss of analyte phosphorus, which normally occurs during the drying and ashing stages, is suppressed. The phosphate ion is reacted with the tungsten supplied from the surface of the TBF to form stable tungsten phosphate species. Regarding the determination of sulfur, additional chemical modifiers such as copper(II), lead(II), etc., are necessary to retain the analyte on the TBF. The furnace-fusion (FF) method or wet-digestion technique on the TBF is applied to unify the chemical forms of the analytes. Various oxidative and reductive inorganic compounds as well as organic compounds of phosphorus and sulfur show the same sensitivities after the FF digestion with hydrogen peroxide. The detection limits are 1.5 ng and 0.12 ng for phosphorous and sulfur, respectively. The repeatabilities in terms of the relative standard deviations of 10 replicate measurements of phosphorus and sulfur are 4.2% and 2.0%, respectively. Finally, the established method is applied to the determination of several environmental waters.     

Use of the inductively coupled plasma mass spectrometry for element analysis of environmental objects

Capabilities and limits of the inductively coupled plasma mass spectrometry (ICP-MS) are discussed by the examples of element analysis of natural and drinking water, soils, ground, bottom sediments, phytogenous samples, and aerosols. It is shown that this method in combination with simpler atomic-emission technique allows for widening the range of detected elements, simplify the mass-spectrometry analysis, and improve its reliability. Examples and metrological characteristics of techniques for studying various environmental objects are discussed.     

顶空-固相微萃取-气相色谱-电感耦合等离子体质谱法联用测定大气颗粒物中的无机汞和甲基汞

大气中的汞有不同的存在形态,对环境的影响程度不同,目前对大气颗粒中汞的测定研究及其形态分析尚非常薄弱。该文尝试将顶空-固相微萃取与气相色谱-电感耦合等离子体质谱法联用测定大气颗粒物中的无机汞和甲基汞。该方法对甲基汞和无机汞的检出限分别为2 ng/L(0.02 ng)和0.5 ng/L(0.005 ng),测定下限分别为8 ng/L(0.08 ng)和2 ng/L(0.02 ng)。可实现大气颗粒物中无机汞的准确测定,也可以用于甲基汞污染情况下污染源废气或污染区大气颗粒物中甲基汞的监测。     

电感耦合等离子体发射光谱法测定矿石中银的研究

目前,实验室测定矿石中银的方法主要有银的光度法、火焰原子吸收光谱法、石墨炉原子吸收光谱法等等,为了更好的简化测量过程、提高工作效率,本文旨在建立更适宜的、能满足于高中低含量银的测试方法,采用电感耦合等离子体光谱法测定金属矿中银的含量.样品采用氢氟酸、硝酸、硫酸(体积比10∶5∶1)溶解,赶净氟和破坏有机物后,经(1+1...     

Determination of platinum and palladium in dead catalysts using inductively coupled plasma atomic emission spectrometry after sample digestion by high-temperature fusion

A technique for the determination of platinum and palladium in dead catalysts using ICP-AES after sample digestion by high-temperature fusion with potassium pyrosulfate is described. The technique is universal; it offers the possibility to analyze various brands of catalysts and their mixtures at a content of platinum and palladium of 0.1% to whole units of percent in a short time. The accuracy of results of determination of platinum and palladium is confirmed by comparison with the data of interlaboratory control. The relative standard deviation in the developed technique is 4–2.5% for the content of platinum and palladium of 0.1 to 0.5% and 2–1% for higher concentrations of these elements.     

Determination of methionine and selenomethionine in selenium-enriched yeast by species-specific isotope dilution with liquid chromatography-mass spectrometry and inductively coupled plasma mass spectrometry detection

Selenomethionine (SeMet) and methionine (Met), liberated by acid hydrolysis of selenium-enriched yeast, were quantified by liquid chromatography-mass spectrometry (LC/MS) using standard additions calibrations as well as isotope dilution (ID) based on species-specific (13)C-enriched spikes. LC inductively coupled plasma mass spectrometry (ICPMS) was also employed for the quantification of SeMet, and (74)Se-enriched SeMet was used for ID calibration. The results were evaluated to ascertain the feasibility of using these methods in a campaign to certify selenized yeast. Good agreement was found between the methods, which, when averaged, gave concentrations of 5482.2 +/- 101 and 3256.9 +/- 217.4 microg/g for Met and SeMet, respectively. This corresponds to a 1.68:1 Met-to-SeMet ratio in the yeast. Quantification by ID LC/MS and LC ICPMS yields the most precise sets of results with relative standard deviations in the range 0.5-1.3% (n = 6). A total selenium concentration of 2064.6 +/- 45.4 microg/g was obtained for this yeast material. The extraction efficiency and a mass balance budget were determined. Acid hydrolysis liberated 81.0% of the total selenium present. SeMet comprised 79.0% of the extracted selenium and 63.9% of the total selenium present in the yeast.