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.     

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.     

Analytical Method Validation and Determination of Iron and Phosphorus in Vegetable Oil by Inductively Coupled Plasma–Mass Spectrometry with Microwave Assisted Digestion

Inductively coupled plasma–mass spectrometric determination of iron and phosphorus in three vegetable oils (soybean, coconut, and sunflower) was validated for the intermediate precision, trueness, linearity, and quantitation limit. The overall precision (n?=?5) for the analytes, which were above the method’s practical limit of quantification, were less than 2% relative standard deviation and the same as the laboratory control, NIST-SRM-1849a. Trueness was demonstrated with spike recoveries of the analytes in all vegetable oils at limit of quantification-level spiking. Although good linearity (regression coefficient greater than 0.9990) obtained, the recovery of phosphorus (156–189%) was high, possibly due to oil matrix enhancement, compared to the recovery of iron (91–106%). For soybean oil, sunflower oil, coconut oil, and medium chain triglycerides, the concentrations (mg/kg) of iron were in the range of 0.10–1.47, 0.09–1.51, 0.20–0.35, and 0.09–0.13, respectively. Similarly, phosphorus concentrations (mg/kg) were in the range of 0.77–124.56, 0.49–125.57, 0.52–9.72, and 0.85–11.90, respectively. The study achieved considerably low instrument-based practical limits of quantification for iron (0.005?mg/kg) and phosphorus (0.05?mg/kg), which are fivefold lower than the AOAC Official Method 2015.06. The high instrument sensitivity and selectivity of the method allow the determination of trace levels of iron and phosphorus in vegetable oils with good precision and trueness.     

Inductively Coupled Plasma Zoom–Time-of-Flight Mass Spectrometry

A zoom–time-of-flight mass spectrometer has been coupled to an inductively coupled plasma (ICP) ionization source. Zoom–time-of-flight mass spectrometry (zoom-TOFMS) combines two complementary types of velocity-based mass separation. Specifically, zoom-TOFMS alternates between conventional, constant-energy acceleration (CEA) TOFMS and energy-focused, constant-momentum acceleration (CMA) (zoom) TOFMS. The CMA mode provides a mass-resolution enhancement of 1.5-1.7× over CEA-TOFMS in the current, 35-cm ICP-zoom-TOFMS instrument geometry. The maximum resolving power (full-width at half-maximum) for the ICP-zoom-TOFMS instrument is 1200 for CEA-TOFMS and 1900 for CMA-TOFMS. The CMA mode yields detection limits of between 0.02 and 0.8 ppt, depending upon the repetition rate and integration time—compared with single ppt detection limits for CEA-TOFMS. Isotope-ratio precision is shot-noise limited at approximately 0.2% relative-standard deviation (RSD) for both CEA- and CMA-TOFMS at a 10 kHz repetition rate and an integration time of 3–5 min. When the repetition rate is increased to 43.5 kHz for CMA, the shot-noise limited, zoom-mode isotope-ratio precision is improved to 0.09% RSD for the same integration time.

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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…     

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.     

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.     

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.     

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.     

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.     

Determination of Rare Earth Elements in Garnet Minerals,Geological Materials by Inductively Coupled Plasma–Atomic Emission Spectral and Mass Spectral Analysis

Abstract

The performance of inductively coupled plasma–atomic emission spectrometry (ICP‐AES) for the determination of 14 lanthanides and Yttrium was evaluated by comparison with inductively coupled plasma–mass spectral (ICP‐MS) analysis. The geochemical reference samples (GRS), DNC‐1(diabase), AGV‐1(andesite), Sy‐2(syenite), MRG‐1(gabbro), AN‐G(anorthosite), AC‐E(granite), and MAG‐1(marine mud) were chosen as test materials and analyzed for checking the precision and reproducibility of the methods. The mineral garnet is separated from the black sands of the southwest coast of India, and the combined cation exchange–ICP method of AES analysis and MS analysis were carried out for the determination of rare earth elements. Both techniques are within the requirements needed for garnet minerals. The determination of rare‐earth elements in these minerals, which contain other elements as major contribution and trace distribution of rare‐earth elements, shows that ICP applied under the proper working condition lives up to the expectations. Major element analysis gives the formula of garnet of Manavalakurichi (MK) as (FeCaMg)_2.79Al_2.07Si_3.05O₁₂ approximated to Fe₃Al₂Si₃O₁₂, hence of almandine-type garnet. The enrichment of heavy lanthanides compared to the light lanthanides indicates that these lanthanides occupy the coordinaton site of Fe²⁺ by replacement. Both techniques are excellent in determining the very low concentration of lanthanides in geological materials, specifically garnet.     

Possibilities of the Determination of Matrix Elements of High-Purity Glasses of As–Se and As–S Systems by Inductively Coupled Plasma Atomic Emission Spectrometry

Possibilities of inductively coupled plasma atomic emission spectrometry (ICP AES) as an alternative to X-ray spectrochemical analysis are estimated in the determination of matrix elements of glasses of As–Se and As–S systems. Standard solutions were prepared from pure elements As, Se and S. It was shown that the matrix elements of glasses can be determined with an expanded uncertainty of 0.05–0.1 mol %. The results of determinations by ICP AES and X-ray fluorescence spectrometry were compared; and it was found that by the attained performance characteristics, the results of ICP AES are highly competitive with the data of X-ray fluorescence spectrometry, but do not require sets of adequate solid reference samples.     

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.     

Minireview: Advances in Germanium Isotope Analysis by Multiple Collector–Inductively Coupled Plasma–Mass Spectrometry

The advent of multiple collector–inductively coupled plasma–mass spectrometry (MC-ICP-MS) has made the high-precision determination of Ge isotopes possible, which leads to the widespread application of Ge isotopes in earth, ocean, and cosmochemistry fields. This paper reviews the history of Ge isotope analysis, chemical dissolution and purification, and mass spectrometry measurements. Concentrated HNO₃ is sufficient to dissolve nearly all types of samples and HF is also involved for Si-rich samples. Low-temperature ashing prior to dissolution is an alternative way to preconcentrate Ge in organic-rich samples. For different matrices, Ge isotopes can be determined by MC-ICP-MS coupled with a traditional nebulizer system or hydride generation system after two-step separation, one step cation/anion-exchange separation, or Mg/Fe co-precipitation protocols. Ion-exchange column methods are suitable for samples with elevated matrix and Ge content such as sulfides, iron oxides, silicate rocks, and coals, whereas Mg or Fe coprecipitation methods are particularly suitable for all kinds of water. Hydride generation systems are improved over traditional nebulizer system due to the smaller sample quantity and fewer matrix-related interferences. Sample-standard bracketing, double spike, and external Ga isotope normalization are used to mass bias correction and yield consistent results. Analytical methods involving Ge-poor samples and Ge isotope analyses based on different Ge species or specific Ge compound in natural environment will be important prospects in the further study. For further applications of Ge isotopes in mineral deposits such as sulfide and iron oxide deposits, sulfides, and iron oxides reference materials should be developed in the future.     

Speciation of Mercury in Terrestrial Plants Using Vapor Generation and Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry

A sensitive method for mercury speciation in biological samples is reported. A simple vapor generation apparatus was coupled to liquid chromatography and inductively coupled plasma–mass spectrometry (ICP–MS) to achieve a substantial increase in sensitivity. Mercury(II) and methylmercury were separated by reversed-phase chromatography as thiolate compounds with 2-mercaptoethanol. A short reverse phase column with an octylated stationary phase (75 × 4 millimeters) was used with a mobile phase containing 0.02 mole per liter ammonium acetate, 0.2 percent (v/v) 2-mercaptoethanol, and 1 percent methanol. The effluent was mixed with hydrochloric acid (0.06 mole per liter) containing platinum (40 micrograms per liter) as the internal standard and bismuth (30 micrograms per liter) as a modifying agent followed by sodium borohydride (0.016 mole per liter). The generated volatile species were introduced into the ICP–MS by conventional solution nebulization. In addition to the sensitivity enhancement induced by vapor generation, the addition of bismuth further increased the methylmercury signal with a reduced increase in the mercury(II) signal. As a result, comparable but unequal signals were achieved: the mercury(II) signal was approximately 1.6-fold higher than the methylmercury signal. Extraction with a hydrochloric acid-2-mercaptoethanol solution was used for sample preparation. The accuracy of determination was verified using two standard reference materials and an interlaboratory reference material based on barley grown hydroponically in mercury-contaminated solution. The method was employed for mercury speciation of plant samples from a polluted region.     

Determination of Rhenium in Seawater from the Jiulong River Estuary and Taiwan Strait,China by Automated Flow Injection Inductively Coupled Plasma–Mass Spectrometry

A novel and automated flow injection (FI) system using a commercially available anion-exchange resin was developed for the online determination of rhenium in seawater by inductively coupled plasma–mass spectrometry (ICP–MS). The flow rate, reagent concentration, and sample volume were optimized. The rhenium concentration was determined using the integrated peak area through interpolation of standard addition calibration curves. The relative standard deviation was less than 2.45% (n?=?5), the recoveries were from 94.59 to 104.11%, and the linear dynamic range of the method was up to 998?ng?kg^?1. There was a good agreement between the rhenium concentrations in a standard measured in this work with results from previous studies. The limit of detection was 0.11?ng?kg^?1 for a sample volume of 7.5?mL and one cycle required 8.33?min. The developed FI–ICP–MS method was used to determine rhenium in seawater from the Jiulong River Estuary and Taiwan Strait.     

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.     

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...     

Determination of Fluoxetine in Human Plasma by Liquid Chromatography–Mass Spectrometry and Its Application

Abstract

A rapid, simple, and specific liquid chromatography–electrospray ionization–mass spectrometric method has been developed and validated for the determination of fluoxetine in human plasma. The method was validated with a linear range of 0.5–100 ng mL^?1, and the lowest limits of quantification were 0.5 ng mL^?1 for fluoxetine. The extraction efficiencies were about 65% and recoveries of method were in the range of 94.0–97.5%. The intraday relative standard deviation (RSD) was less than 11% and interday RSD was within 12%. The method has been successfully applied to the evaluation of pharmacokinetics and bioequivalence of fluoxetine.     

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…