Study of the Chromium Distribution in New Materials Based on Tin Dioxide by Inductively Coupled Plasma–Mass Spectrometry

Moscow University Chemistry Bulletin - A new approach to determine additions of chromium and study its distribution in the bulk and on the surface of SnO2-based nanocrystalline semiconductor...     

Analysis of Niobium–Rare-Earth Ores by Inductively Coupled Plasma Mass Spectrometry

To determine the composition of niobium–rare-earth ores by atomic emission spectrometry and inductively coupled plasma mass spectrometry, two procedures are developed for sample preparation based on autoclave decomposition and flux fusion. Autoclave decomposition is carried out in a mixture of HF and HNO₃ at a temperature of up to 220°C and a pressure of up to 160 atm using a developed system with resistive heating. Subsequent evaporation to dry salts ensures the removal of F^– ions and silicon as SiF₄. The residue is dissolved in a mixture of HCl and H₂O₂ at 160°C under elevated pressure. The resulting solutions (10% with respect to HCl with the addition of H₂O₂) are diluted before measurements. The dissolution process is monitored for each sample using stable highly enriched isotopes of ⁹¹Zr, ¹⁰⁰Mo, ¹⁴⁹Sm, and ¹⁷⁸Hf. The second procedure is based on fusing samples with a mixture of Na₂CO₃ and Na₂B₄O₇ at 1050°C in a muffle furnace and dissolving the resulting melt in a mixture of HCl and H₂O₂. The procedures were tested using the national (NFS-23) and foreign standard samples of composition (OREAS-462, 463, 464, 465, Australia) and real samples of niobium–rare-earth ores.     

Multielement Analysis of South Serbian Strawberry Cultivars by Inductively Coupled Plasma—Optical Emission Spectrometry

The contents of 17 elements in thirteen strawberry cultivars grown in the five districts of Southern Serbia were determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The most abundant elements are K (875–1148 mg?·?kg^?1 fresh weight), P (307–664 mg?·?kg^?1 fresh weight), Ca (192–256 mg?·?kg^?1 fresh weight), and Mg (111–189 mg?·?kg^?1 fresh weight) in all samples. Strawberries were also found to be a good source of Sr (8.05–18.6 mg?·?kg^?1 fresh weight) and Fe (3.09–10.4 mg?·?kg^?1 fresh weight). The contents of As and Cd were below the detection limit (0.0828 mg?·?kg^?1 and 0.0205 mg?·?kg^?1, respectively) in all strawberry samples, while the contents of Ni, Cr, and Cu were below the recommended tolerable levels proposed by Joint Food and Agriculture Organization of the United Nations and World Health Organization Expert Committee on Food Additives, and did not a pose a health risk for the consumer. The application of Duncan’s test showed significant differences between contents of analyzed elements in all strawberry cultivars. The highest mean levels of analyzed elements were detected in strawberries grown in the Topli?ki, Jablani?ki, and P?injski districts. The spike recovery test was used to verify the accuracy of the method, and the spike recovery was in the range 93.8–107.8%. The contents of the metals in strawberry samples were also comparable with values previously reported in the literature.     

Studies on Volatilization of Zirconium from Electrothermal Graphite Furnace for Sample Introduction into Inductively Coupled Plasma

Element zirconium reacted with polytetrafluoroethylene (PTFE) dispersed in isopropanol-water mixture to form volatile fluoride when heated in an electrothermal graphite furnace, and the fluorides formed subsequently were vaporized into ICP for atomization and excitation. The technique provides a picogram detectkm limit and adequate precision of 4% relative standard deviation. Linear dynamic range covers over three orders of magnitude. The process of sample preparation it very convenient. It is expected that the method proposed is suitable for determination of other refractory elements.     

Elemental Analysis of Phytotherapeutic Products by Inductively Coupled Plasma–Tandem Mass Spectrometry

A procedure for the determination of As, Cd, Cr, Ni, Pb, and V in phytotherapy medicines by inductively coupled plasma–tandem mass spectrometry is reported. The use of tandem mass spectrometry with oxygen into an octopole reaction system at various gas flow rates and the combination of on-mass and mass-shift modes was evaluated. Cadmium, Cr, Ni, and Pb were determined as free atomic ions while As and V were determined as the oxides AsO⁺ and VO⁺ in the same run. Samples were prepared by microwave-assisted digestion with dilute nitric acid and hydrogen peroxide. Two plant-certified reference materials (apple leaves and tomato leaves) were used to check the accuracy. For tandem mass spectrometry with 0.5?mL min^?1 O₂, recoveries in the 85–113% were typically obtained and no statistical differences were observed at the 95% confidence level (t-test) in comparison with the certified values. Using these conditions, the limits of detection for the method were 0.01, 0.0002, 0.008, 0.008, 0.003, and 0.002?µg g^?1 for As, Cd, Cr, Ni, Pb, and V, respectively. The procedure was used for the analysis of four phytotherapic drugs and the determined concentrations were up to 0.168?µg g^?1 As, 0.03?µg g^?1 Cd, 0.82?µg g^?1 Cr, 1.18?µg g^?1 Ni, 0.52?µg g^?1 Pb, and 2.4?µg g^?1 V with average precision values of 8% as the relative standard deviation. The found concentrations were compared with limits proposed in official guidelines and, in most cases, the values were below the maximum limits allowed.     

Multielemental Analysis of Human Serum by Dynamic Reaction Cell–Inductively Coupled Plasma Mass Spectrometry

The selection of the most suitable dilution methods for determination of trace elements in human serum using inductively coupled plasma mass spectrometry is reported. The trace elements were Al, V, Cr, Fe, Mn, Co, Cu, Zn, As, Cd, Sn, Tl, and Pb. The performance of various dilution methods was assessed by precision, linearity, detection limits, quantification limits, fortified recoveries, and the analysis of reference materials. The results demonstrate that diluted solution containing only nitric acid is most suitable for As, Cr, Mn, and Co in serum. Dilute solutions containing nitric acid and Triton X-100 were most appropriate for Cu, Zn, Cd, and Tl. The optimum conditions for Al, V, Mn, Fe, Cr, Co, Sn, and Pb used tetra-n-butylammonium hydroxide, Triton X-100, and ethylenediamine tetraacetic acid.     

Preliminary Study on Pyrolysis of Polymethylsilsesquioxane by FT—IR and XPS

The term polysilsesquioxanes in this paper refers to all structures with the empiri-cal formulas (RSiO3/2)n where R is hydrogen or any alkyl, alkylene, aryl, arylene, or organo-functional derivatives of alkyl, alkylene, or aryl. Polymethylsilsesquioxane (PMSQ) is characterized by its low weight loss at high temperatures. X-ray photoelectron spectroscopy (XPS) characterization of PMSQ was unavailable from reported literatures. In this study, the pyrolysis was carried out in an inert at…     

High-Sensitivity and High-Performance Determination of Trace Aluminum in Water for Pharmaceutical Purposes by Microwave Plasma and Inductively Coupled Plasma–Atomic Emission Spectrometry

Procedures for the determination of aluminum in water for injections (Aqua ad iniectabilia) and high-purity water (Aqua valde purificata) at a level of several µg?L^?1 using atomic-emission spectrometry with a novel microwave plasma (MP–AES) and inductively coupled plasma (ICP–AES) are proposed. Regardless of the atomic-emission technique used, the procedure for aluminum needs no sample preparation (acidification only), no preconcentration, shows high sensitivity (limits of detection of 0.4 and 0.7?µg?L^?1 for ICP–AES and MP–AES with a polymeric inert concentric nebulizer, respectively, and 0.03?µg?L^?1 for ICP–AES with an ultrasonic nebulizer), high precision (repeatability, relative standard deviation, <5%), and high throughput (25 samples per hour), and is considerably simpler and more expedient from the viewpoint of the analysis cost and time compared with the standard spectrofluorimetric procedure of the US and the European Pharmacopoeia.     

Matrix Effects and Behaviors of Elements in Oxalic Acid Medium by Inductively Coupled Plasma Mass Spectrometry

Because of its high sensitivity, wide dynamic range and relative freedom from interferences, inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of trace and ultra-trace levels of elements in various fields1. Due…     

Rapid Speciation of Lead in Water by High-Performance Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry

The rapid speciation of lead is reported by high performance liquid chromatography and inductively coupled plasma – mass spectrometry. The separation of inorganic lead, trimethyllead, triethyllead and triphenyllead was achieved within 3.5 minutes on a C₁₈ column using a gradient program of methanol and water containing 5 milligrams per liter sodium 1-pentanesulfonate at pH 5. The limits of detection for inorganic lead, trimethyllead, triethyllead, and triphenyllead were 0.01, 0.02, 0.02, and 0.02 micrograms per liter, respectively. The accuracy of the method was verified by the analysis of water (GSBZ 50009-88) and seawater (GBW (E) 080040) certified reference materials. The method was also employed for the analysis of water samples; inorganic lead was measured in river water.     

Quantification of Trace Amounts of Impurities in High Purity Cobalt by High Resolution Inductively Coupled Plasma Mass Spectrometry

Cobalt metal has been used in the production of magnetic alloys, cobalt and nickel based superalloys and sputtering targets in the field of advanced electronic devices1. The determination of trace impurities in high purity cobalt is extremely important be…     

Determination of Essential and Toxic Elements in Tropical Fruit by Microwave-Assisted Digestion and Inductively Coupled Plasma–Mass Spectrometry

The concentrations of eight essential (Co, Cr, Cu, Mn, Ni, Se, V, and Zn) and five toxic elements (Al, As, Cd, Hg, and Pb) were determined in 457 samples of commonly consumed fresh tropical fruit including bananas (Musa acuminata), kiwi (Actinidia deliciosa), mangos (Mangifera indica), and pineapple (Ananas comosus) from supermarkets from Seoul, Busan, Gangneung, Daegu, Daejeon, and Gwangju, South Korea. The samples were digested by microwave-assisted combustion using HNO₃ and H₂O₂ and determined by inductively coupled plasma mass spectrometry. The Hg concentrations were evaluated by furnace-gold amalgamation direct mercury analysis. The techniques were validated by linearity, limits of detection and quantification, precision, recovery, and the analysis of a NIST-1570a spinach leaves certified reference material. The concentrations of essential elements varied considerably among the tropical fruit. Overall, the tropical fruit was higher in Mn (0.027–13.2?µg/g) and Zn (0.514–2.20?µg/g), while lower in Co (0.002–0.005?µg/g) and V (0.001–0.002?µg/g). The concentrations (µg/g) of toxic elements were 0.001 (kiwi) to 0.003 (mango) for As and Cd, 0.0004 (pineapple) to 0.002 (banana) for Hg, and 0.005 (kiwi) to 0.013 (mango) for Pb. The calculated values of estimated dietary intake, target hazard quotients and hazard indices were lower than one and the safety limits established by World Health Organization. The tropical fruits were therefore safe and did not pose any threat to consumers.     

Determination of Phosphorus in Crude Oil and Middle Distillate Petroleum Products by Inductively Coupled Plasma–Optical Emission Spectrometry

A method for the precise and accurate determination of phosphorus in crude oil and middle distillate petroleum products was developed using inductively coupled plasma–optical emission spectrometry to rapidly determine phosphorus as a control method. The presence of phosphorus is undesirable in petrochemical products as it complexes with other metals generating residues that interrupt normal operation of refineries. The presence of phosphorus may be due to some anti-fouling additives or the crude oils processed. Consequently, it is necessary to control the phosphorus present at trace levels in the crude oil and in process streams that present various densities and viscosities. The instrumental power, nebulizer flow, pump rate, read time, and the sample preparation conditions were optimized. The desired level of quantification for the petrochemical industry was achieved allowing the simultaneous analysis of diverse liquid petroleum products.     

Trace Determination of Manganese in Urine by Graphite Furnace Atomic Absorption Spectrometry and Inductively Coupled Plasma–Mass Spectrometry

This paper describes a simple and sensitive method for the determination of manganese in human urine by graphite furnace atomic absorption spectroscopy (GFAAS), which includes sample preparation by microwave digestion. Matrix modifier combinations, the digestion power, pyrolysis, and atomization temperatures were optimized. A mixture of 5.0 µg Pd(NO₃)₂ and 3.2 µg Mg(NO₃)₂ modifier presented the best performance. The optimal temperatures for pyrolysis and atomization were 1500°C and 1950°C, respectively. The GFAAS method was compared to inductively coupled plasma–mass spectrometry (ICP–MS) for the determination of manganese in urine. Analytical figures of merit for GFAAS and ICP–MS were: accuracy (3.46%, 2.19%), precision (3.61%, 5.84%), LOD (0.109 µg · L^?1, 0.015 µg · L^?1), LOQ (0.327 µg · L^?1, 0.045 µg · L^?1), and recovery (80–100%, 74–89%). Both methods were employed for the determination of Mn in urine and the results were compared statistically.     

Simulation of Gas-Dynamic and Thermal Processes in Vortex-Stabilized,Inductively Coupled Argon–Hydrogen Plasma

The flow of vortex-stabilized argon–hydrogen plasma in a radiofrequency induction (RFI) plasma torch has been investigated using modern methods of computational fluid dynamics. Optimal values of the torch power and energy release in plasma have been found at various argon to hydrogen ratios in the plasma gas mixture. The heat and kinetic fields determined by calculation for a plasma-chemical reactor can be of use in designing an RFI plasma torch in part concerning the determination of the optimum zone for feeding the reactants to the reactor.     

Determination of Organotin Compounds in Wine by Microwave-Assisted Extraction and High Performance Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry

A new analytical procedure for the determination of five organotin compounds in several matrix wine samples is reported. The organotin compounds were extracted by microwave-assisted extraction with n-hexane. Extraction conditions, such as volume of n-hexane required, extraction temperature, and extraction time, were investigated and optimized by an orthogonal array experimental design. The determination of organotin compounds in the final extracts was carried out by liquid chromatography–inductively coupled plasma mass spectrometry. The procedure showed limits of detection between 0.029–0.049 µg · L^?1. The linearity was in the range of 0.5 to 100 µg · L^?1. The precision expressed as relative standard deviation (RSD) was below 9.43%. The developed method was successfully employed to analyze different matrix wine samples, and some analytes were detected at the level of 0.053 to 1.14 µg · L^?1.     

Carbon Nanofibers as Solid‐Phase Extraction Adsorbent for the Preconcentration of Trace Rare Earth Elements and Their Determination by Inductively Coupled Plasma Mass Spectrometry

Abstract

Systematic investigations were carried out into the sorption of rare earth elements (REEs) on carbon nonofibers (CNFs) by inductively coupled plasma mass spectrometry (ICP‐MS). The experimental parameters for preconcentration of REEs, such as pH, sample flow rate and volume, eluent concentration, and interfering ions on preconcentration of REEs have been examined in detail. The studied metal ions can be adsorbed quantitatively on CNFs in a pH range from 2.0 to 5.0, and then eluted completely with 0.5 mol l^?1 HNO₃. Based on the above facts, a novel method using a microcolumn packed with carbon nanofibers as an adsorption material was developed for the separation and preconcentration of REEs prior to their determination by ICP‐MS. The proposed method has been successfully applied to the determination of light (La), medium (Eu and Gd) and heavy (Yb) rare earth elements in real sample with the recovery more than 90%. In order to validate this method, two certified reference materials of tea leaves (GBW 07605) and mussel (GBW 08571) were analyzed, and the determined values are in good agreement with the certified values.     

Speciation of Volatile Selenium Species in Plants Using Gas Chromatography/Inductively Coupled Plasma Mass Spectrometry

 Gas chromatography/inductively coupled plasma mass spectrometry (GC/ICP MS) coupled with solid phase micro extraction can provide a simple, extremely selective and sensitive technique for the analysis of volatile sulfur and selenium compounds in the hea     

Determination of Heavy Metals in Crawfish (Procambrus clarkii) by Inductively Coupled Plasma–Optical Emission Spectrometry: A Study over the Season in Southwest Louisiana

Abstract

Six metals (cadmium, copper, nickel, lead, iron, and zinc) were determined by inductively coupled plasma–optical emission spectrometry in crawfish (tails and whole bodies) and soil in the vicinity of the crawfish, in a season of 4 months (February through May) in southwest Louisiana. Cadmium and lead were not found in the tail or whole body. Nickel was found in some samples of tail but mostly in the April and May samples. Copper, iron, and zinc were found in both tail and whole body of the crawfish. Limited soil sampling showed no cadmium, nickel, or copper in soil, but levels of iron, lead, and zinc were detected.