Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0268318 (ICP)
 10,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.
 ...
PMID:234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples. 1654 93

A method is described for determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry with an octapole reaction cell (ID-ICP-ORCMS). Sediment samples were digested with HNO3, HClO4, and HF, and the digestion included an elaborate evaporation process to remove bromine from the digested solution. Simple strong cation-exchange disk filtration was used to remove rare earth elements (REE) from the digested solution, because REE2+ seriously interfere with Se isotopes (i.e. 156Gd2+ with 78Se+, 160Gd2+ with 80Se+). Addition of acetic acid to the filtrate was examined to improve the sensitivity of ICP-ORCMS measurement of Se+ by means of a carbon-enhancement effect. The interfering Ar2+ for selenium isotopes were almost eliminated by use of H2 as reaction gas. Interference from BrH+ formed in the reaction cell was negligible because the Br was removed in the evaporation process. Approximately 99.5% of REE were removed by cation-exchange disk filtration yet more than 99% of Se remained in the filtrate solution. The intensity for Se+ was enhanced approximately fourfold by addition of 5% (v/v) of acetic acid whereas that for Ar2+ was barely enhanced. Measured 80Se/78Se ratios in unspiked digested solutions of the sample were in good agreement with that for an Se standard solution. The analytical results for Se in the certified reference materials MESS-3 and PACS-1 were in good agreement with their certified values, with small uncertainties.
 ...
PMID:Determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry with an octapole reaction cell. 1655 8

A method was developed for high-throughput determinations of 7 elements in food samples, namely antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and tin (Sn). The samples were digested by closed-vessel microwave-assisted digestion using concentrated nitric acid (HNO3) as the medium, followed by microwave- assisted evaporation to concentrate the sample solutions before dilution to the desired volume. The microwave-assisted evaporation procedure effectively reduced the final acid concentration to around 8% before analysis by inductively coupled plasma-mass spectrometry (ICP-MS). This reduction allows determination by ICP-MS to proceed without further sample dilution, which would affect the detection limit. The method was validated, and method recoveries for As, Cd, Cr, Pb, and Hg were within the certified ranges of the chosen certified reference materials. Recoveries of the 7 elements from spiked samples ranged from 93.1 to 103.6%. The standard uncertainties of precision for the 7 elements were between 3.1 and 4.3%. Interlaboratory comparison studies for As, Cd, and Pb gave z-scores ranging from -0.2 to 0.3.
 ...
PMID:High-throughput determination of seven trace elements in food samples by inductively coupled plasma-mass spectrometry. 1664 Feb 96

Soil metal surveys were conducted in Baltimore, MD (1976-1979), Minnesota (1981-1988) and most recently, New Orleans, LA (1989-present). The unique characteristic of New Orleans is that it has two surveys; Survey I was completed in 1992 and Survey II was completed in 2000. This paper seeks to determine if there is a perceptible change in the amount of metals during less than a decade that separated these surveys. The Survey I collection was 4,026 samples stratified by 283 census tracts. All samples were collected in residential neighborhoods at least one block from a busy street. The Survey II collection was 5,467 samples stratified by 286 census tracts (plus City Park). The Survey II collection included busy streets as a category of samples. For comparison, the busy street category of 1,078 samples was excluded from Survey II for a total of 4,388 samples. The extraction methods of the two surveys used the same protocol for strength of acid (1 M HNO3), shaker-time (2 hours), and room temperature (approximately 22 degrees C). However, Survey II differed in amount of sample used in extraction. For Surveys I and II, 4.0g and 0.4g were used respectively. The same ICP-AES was used to measure 8 metals in both surveys. To evaluate the analytical results of the two methods, reference soi 1 samples (n=36) from the Wageningen Evaluating Programs for Analytical Laboratories, International Soil-analytical Exchange (WEPAL; ISE) were used. The relationship between the 4.0 and 0.4 g results were linear and the Survey I results were adjusted for sample:acid ratio. Further evaluation was done by creating interpolated Multiple Metal Accumulation (MMA) maps based on the median MMA for each census tract. A new map was created by dividing Survey II MMA by Survey I MMA. The ratio indicates increases of soil metals in the inner city and decreases of soil metals in the outlying areas of Metropolitan New Orleans. Comparing fresh parent alluvium from the Mississippi River with urban soil metal quantities demonstrates that the soils of New Orleans have undergone a massive accumulation of metals. The preliminary results provide ideas about methods needed to further evaluate the changes between these surveys.
 ...
PMID:Changes of multiple metal accumulation (MMA) in New Orleans soil: preliminary evaluation of differences between survey I (1992) and survey II (2000). 1670 33

A method for the determination of Ti and V using inductively coupled plasma atomic emission spectrometry (ICP OES) in Ziegler-Natta polymerization catalysts is proposed. The concentrations of both Ti and V are efficiently determined after catalyst acid digestion with a mixture of HNO3 + HCl + HF and heating (160 degrees C for 6 h) or with 10% (v/v) H2SO4 and heating (160 degrees C for 6 h) or with 10% (v/v) H2SO4 and sonication (during 2 min). The V and Ti detection limits are 0.002% and 0.08%, respectively, using 0.20 g of catalyst sample in 50 ml. The method is validated by a comparison with the Rutherford backscattering spectrometry (RBS) technique. In this case, catalyst samples are only pressed as pellets before analyte determination. Despite the fact that both the V and Ti concentrations cannot be determined individually by means of RBS, because the atomic numbers of Ti and V are very close, the sum of the V and Ti contents is in accordance with that attained by means of ICP OES. According to scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) it is observed that the Ti distribution on the catalyst grain is not homogenous.
 ...
PMID:Determination of titanium and vanadium in Ziegler-Natta catalysts by inductively coupled plasma atomic emission spectrometry. 1677 85

A new sorbent, maleic acid grafted polytetrafluoroethylene fiber (MA-PTFE), was prepared and evaluated for on-line solid-phase extraction coupled with inductively coupled plasma mass spectrometry (ICP-MS) for fast, selective, and sensitive determination of (ultra)trace rare earth elements (REEs) in environmental samples. The REEs in aqueous samples at pH = 3.0 were selectively extracted onto a microcolumn packed with the MA-PTFE fiber, and the adsorbed REEs were subsequently eluted on-line with 0.9 mol l(-1) HNO3 for ICP-MS determination. The new sorbent extraction system allows effective preconcentration and separation of the REEs from the major matrix constituents of alkali and alkali earth elements, particularly their separation from barium that produces considerable isobaric interferences of 134Ba16O1H+, 135Ba16O+, 136Ba16O1H+, and 137Ba16O+ on 151Eu+ and 153Eu+. With the use of a sample loading flow rate of 7.4 ml min(-1) for 120 s preconcentration, enhancement factors of 69-97 and detection limits (3s) of 1-20 pg l(-1) were achieved at a sample throughput of 22 samples h(-1). The precision (RSD) for 16 replicate determinations of 50 ng l(-1) of REEs was 0.5-1.1%. The developed method was successfully applied to the determination of (ultra)trace REEs in sediment, soil, and seawater samples.
 ...
PMID:Flow injection on-line solid phase extraction coupled with inductively coupled plasma mass spectrometry for determination of (ultra)trace rare earth elements in environmental materials using maleic acid grafted polytetrafluoroethylene fibers as sorbent. 1681 61

Direct determination of tellurium in geological samples by inductively coupled plasma mass spectrometry (ICP-MS) is often complicated by its low abundance, poor analytical sensitivity, and the presence of xenon interferences. Therefore, a simplified and rapid method for direct determination of nanogram levels of tellurium in geological samples using ICP-MS by reduction of interferences and improvement of sensitivity was developed. It is impossible to resolve 126Te and 128Te from isotope interferences of Xe even by currently available high-resolution magnetic mass spectrometry due to the extremely small mass difference (0.001-0.002 amu). However, the addition of 4% ethanol was found to suppress the interferences of Xe by a factor of 6 and increases the sensitivity of Te determination in ICP-MS by a factor of 3 relative to the values obtained in conventional 3% (v/v) HNO3 solution at the corresponding optimum operating conditions, respectively. The detection limits of 126Te and 128Te were reduced by a factor of 7.2 and 8.8, respectively, and the limit of quantitation (LOQ) for 126Te in the presence of 4% ethanol was 1.5 ng g(-1) (the LOQ is expressed as the concentration in the solid samples, thereby taking into account the dilution factor of 1000). The agreement between the determined Te concentration values (r = 0.998) in various geological samples (n = 140) by using isotopes of 126Te and 128Te indicates negligible contributions of polyatomic interferences produced by the addition of ethanol at these m/z. The proposed method was successfully applied to the direct determination of nanogram levels of Te in a series of international geological reference materials.
 ...
PMID:Direct determination of tellurium in geological samples by inductively coupled plasma mass spectrometry using ethanol as a matrix modifier. 1685 66

The two oxidation states of thallium, Tl(I) and Tl(III), were quantified by IC-ICP-MS using complexation of Tl3+ with DTPA (penta-carboxymethyl-diethylenetriamine) and separation on a cation exchange column according to a modification of the method devised by Coetzee et al. In order to avoid successively lowered separation efficiency and loss of resolution during a run, a gradient elution was made using HCl instead of HNO3. With an ultrasonic nebuliser instead of a V-groove nebuliser the limit of detection for Tl(I) and Tl(III) could be lowered from 25 ng/L and 3.0 ng/L to 9.0 ng/L and 0.7 ng/L, respectively, which is adequate for many fresh water systems. The stability of Tl(III) in acidic solutions was found to be concentration dependent, with an initially high reduction rate of Tl(III). Exposure of the sample to light further increased the reduction rate. Addition of DTPA (0.01 mM) and acid (HNO3, 1%) to a sample with 1 mug/L Tl(III) stabilised the Tl(III) content for at least 48 h. Analysis of field samples showed that only acidification is inadequate to maintain the original distribution of Tl(I) and Tl(III). Internal calibration (standard addition) and correction of the analytical signal (205Tl) with a non-ionic internal standard (11B) yielded almost quantitative recoveries of both Tl(I) and Tl(III). A scheme for field sample preparation is proposed, including sampling, storage and pre-analysis treatment.
 ...
PMID:Separation and quantification of Tl(I) and Tl(III) in fresh water samples. 1685 92

A method is presented for the simultaneous determination of Cr(III) and Cr(VI) in yeast using species-specific double-spike isotope dilution (SSDSID) with anion-exchange liquid chromatography (LC) separation and sector field inductively coupled plasma mass spectrometric (SF-ICP-MS) detection. Total Cr is quantitated using ID SF-ICP-MS. Samples were digested on a hot plate at 95+/-2 degrees C for 6 h in an alkaline solution of 0.5 M NaOH and 0.28 M Na2CO3 for the determination of Cr(III) and Cr(VI), whereas microwave-assisted decomposition with HNO3 and H2O2 was used for the determination of total Cr. Concentrations of 2,014+/-16, 1,952+/-103 and 76+/-48 mg kg-1 (one standard deviation, n=4, 3, 3), respectively were obtained for total Cr, Cr(III) and Cr(VI) in the yeast sample. Significant oxidation of Cr(III) to Cr(VI) (24.2+/-7.6% Cr(III) oxidized, n=3) and reduction of Cr(VI) to Cr(III) (37.6+/-6.5% Cr(VI) reduced, n=3) occurred during alkaline extraction and subsequent chromatographic separation at pH 7. Despite this significant bidirectional redox transformation, quantitative recoveries for both Cr(III) and Cr(VI) were achieved using the SSDSID method. In addition, mass balance between total Cr and the sum of Cr(III) and Cr(VI) concentrations was achieved. Method detection limits of 0.3, 2 and 30 mg kg-1 were obtained for total Cr, Cr(VI) and Cr(III), respectively, based on a 0.2-g sub-sample.
 ...
PMID:Application of double-spike isotope dilution for the accurate determination of Cr(III), Cr(VI) and total Cr in yeast. 1695 11

A procedure was developed for the determination of Cd, Cu, Zn, Co, Ni, Mn, Pb and Mo in water samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) after preconcentration on a morpholine dithiocarbamate (mor-DTC) supported by bagasse (Saccharam aphisinaram). The sorbed elements were subsequently eluted with 4,M HNO3 and the acid eluates were analysed by ICP-AES. The influence of various parameters such as pH, flow rate of sample, eluent concentration, volume of the sample and volume of eluent were investigated to enhance the sensitivity of the present method. A 20,mL disposable syringe served as preconcentration column. Under the optimal conditions Cd, Cu, Zn, Co, Ni, Mn, Pb and Mo in aqueous sample was concentrated about 100-fold. The sorption recoveries of elements were higher than 99.6%. The method is also applied for the analysis of natural and spiked water samples.
 ...
PMID:Preconcentration technique for the determination of trace elements in natural water samples by ICP-AES. 1695 50


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>