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 new method for determination of trace gold (Au), palladium (Pd), and platinum (Pt) in environmental and geological samples by electrothermal vaporization (ETV)-inductively coupled plasma atomic emission spectrometry (ICP-AES) with the use of chelating resin YPA(4) as both solid phase extractant and chemical modifier has been developed. The resin loaded with analytes was prepared to slurry and directly introduced into the graphite furnace without any pretreatment. The factors affecting the vaporization behaviors of Au, Pd, and Pt were investigated in detail. It was found that, in the presence of YPA(4), Au and Pd could be quantitatively vaporized at lower vaporization temperature of 1900 degrees C. Compared with the conventional electrothermal vaporization, the vaporization temperature was decreased by 700 degrees C, and the detection limits for Au and Pd was decreased by a three-fold. However, a little effect of YPA(4) on the ETV-ICP-AES determination of Pt was found. Under the optimized conditions, the detection limits (3sigma) of Au, Pd, and Pt for this method are 75, 60, and 217pg, respectively; and their relative standard deviations (R.S.D.) are 4.4, 5.6, and 3.7%, respectively (n=9, C=0.2mugml(-1)). The proposed method has been applied to the determination of trace Pd and Pt in sewage sludge, and the results well agreed with the recommended values. In order to further verify the accuracy of the developed method, a GBW07293 certified geological reference material and an auto catalyst NIST SRM 2557 reference material were analyzed, and the determined values coincided with the certified values very well.
 ...
PMID:Electrothermal vaporization inductively coupled plasma atomic emission spectrometry determination of gold, palladium, and platinum using chelating resin YPA(4) as both extractant and chemical modifier. 1896 73

The authors have previously reported the use of laser ablation ICP-MS as a powerful analytical tool for elemental analysis of glass. LA is a simpler, faster and less intrusive sample introduction method than the conventional solution ICP-MS. Due to the minute amount of material removed in LA ( approximately 300ng, 50mum crater size), the analyst should be aware of special sampling considerations such as characterization of the glass fragments originating from the "known" source, fragment size and selection of the area and surface of ablation. The purpose of this work was to evaluate the micro-homogeneity of the elemental composition of glass samples commonly found in crime scenes like containers, architectural windows and windshields. The set of glasses under study was comprised of 56 fragments originated from glass containers, 28 fragments from automobile windshields and 20 fragments from architectural windowpanes. All fragments were selected with a size smaller than 2mm(2) in order to simulate the typical glass fragments transferred from the crime scenarios. A Nd:YAG laser, 266nm, flat top beam profile was used in single point mode sampling 50mum spot size for 50s at 10Hz (500 shots). In this study, (29)Si was used as an internal standard and the standard reference material, SRM NIST 612, was used as a single point external calibrator. In addition, SRM 621 was used as another control standard for the containers set and SRM 1831 for the automobile and architectural window sets due to their very similar matrix with the samples of interest. For each set of glasses, the mean values and standard deviation of 10 replicates (n=10) of a single fragment were compared with the values obtained from 10 (n=10) different fragments of glass within the area of interest in order to evaluate whether or not the variation within a glass was bigger than the variation due to the method. In addition, a subset of tempered glasses was evaluated to perform an elemental composition profile within different depths of the fragments. Single shot (one laser pulse per analysis) was also evaluated and its limitations for the forensic analysis of glass are also presented. The results show that float glass is homogenous even at the micro-range level allowing LA-ICP-MS as an alternative technique to perform elemental analysis of glass. However, the variation of elemental composition of headlamps and containers is larger over the source than the instrumental variation due to inherent heterogeneity and therefore specific statistical methods are recommended to compare the glass samples.
 ...
PMID:Sampling strategies for the analysis of glass fragments by LA-ICP-MS Part I. Micro-homogeneity study of glass and its application to the interpretation of forensic evidence. 1897 Jan 80

Glass fragments recovered from crime scenes are usually very small and therefore the amount of sample available to conduct forensic analyses is limited. Elemental analysis using conventional digestion methods consumes at least 2-3mg of glass per replicate. LA-ICP-MS requires 10,000 times less glass consumption per analysis ( approximately 280ng), and therefore the sample remains practically unaltered. Typically, the recovered fragments (unknowns) are 0.1-1mm in length, while the "known" samples are usually larger, i.e. a broken fragment from a windshield (>3mm). For bulk digestion analysis, the difference in fragment size does not present a problem for elemental comparisons - other than requiring at least 6mg for triplicate analysis - because the sample is crushed and homogenized before weighing. Laser ablation sampling results in the creation of small craters ( approximately 50mum diameter and 80mum deep) drilled into the sample due to the interaction of the laser with the glass target. This study aims to evaluate whether the quantitative elemental analysis using the LA sampling method is affected by the size of the glass fragment due to differences in heat dissipation and surface-laser interaction. The analytical method employed for the analysis of glass by LA-ICP-MS had previously shown to possess the same or better performance than dissolution ICP-MS methods in terms of accuracy, precision, limits of detection and discrimination power. A 266nm Nd:YAG laser with a flat top beam profile was used in single point mode sampling a 50mum spot size for 50s at 10Hz. Standard glass reference materials SRM 612 and SRM 610 were selected to conduct this work in order to account for different concentration ranges and different opacities of the samples. The set under study was comprised of seven fragments originating from each standard at different sizes and shapes ranging from 6 to 0.2mm length. Analysis of variance (ANOVA) followed by the Tukey's honestly significant different test (HSD) was used for data analysis. The results show that there is no significant difference in the elemental composition of different sized fragments. The conclusions, however, cannot be generalized for fragments measuring less than 0.2mmx0.1mm.
 ...
PMID:Sampling strategies for the analysis of glass fragments by LA-ICP-MS Part II: Sample size and sample shape considerations. 1897 Jan 81

A novel microwave-assisted wet-acid decomposition method for the multi-element analysis of glass samples using inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed and optimized. The SRM 621 standard reference glass material was used for this purpose, because it has similar composition with either archaeological glass specimens or common modern glasses. For the main constituents of SRM 621 (Ca, Na, Al, Fe, Mg, Ba and Ti), quality control data are given for all the examined procedures. The chemical and instrumental parameters of the method were thoroughly optimized. Thirteen acid mixtures of hydrochloric, nitric, and hydrofluoric acids in relation to two different microwave programs were examined in order to establish the most efficient protocol for the determination of metals in glass matrix. For both microwave programs, an intermediate step was employed with addition of H(3)BO(3) in order to compensate the effect of HF, which was used in all protocols. The suitability of the investigated protocols was evaluated for major (Ca, Na, Al), and minor (Fe, Mg, Ba, Ti, Mn, Cu, Sb, Co, Pb) glass constituents. The analytes were determined using multi-element matrix matched standard solutions. The analytical data matrix was processed chemometrically in order to evaluate the examined protocols in terms of their accuracy, precision and sensitivity, and eventually select the most efficient method for ancient glass. ICP-AES parameters such as spectral line, RF power and sample flow rate were optimized using the proposed protocol. Finally, the optimum method was successfully applied to the analysis of a number of ancient glass fragments.
 ...
PMID:Optimized microwave-assisted decomposition method for multi-element analysis of glass standard reference material and ancient glass specimens by inductively coupled plasma atomic emission spectrometry. 1897 Apr 84

A microwave digestion method with HNO(3) alone was conducted at a temperature as high as 250 degrees C for determination of 19 trace elements (Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Cd, Cs, Ba, Hg, and Pb) in coal jointly by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and flow injection ICP-MS (FI-ICP-MS). The validity of determination was assessed by using three standard coals, SRM 1632c, BCR 180, and SARM 19. It was found that the high-temperature digestion led to an extensive decomposition of the organic matrix and clay in coal, and no dissolved and solid carbon remained in the final solution after evaporation. Good recoveries were observed for all trace elements in three coals, with the exception of V, Rb, and Cs in high-ash SARM 19. Additionally, FI-ICP-MS combined with the present digestion without evaporation pretreatment was proved to be a rapid and efficient approach for determination of ultra-trace elements such as Se, Cd, and Hg in coal.
 ...
PMID:Single-step microwave digestion with HNO(3) alone for determination of trace elements in coal by ICP spectrometry. 1897 May 2

The optimisation of a micro-analytical two-step sequential leaching procedure for the determination of non-volatile ions (NO(3)(-), SO(4)(2-), Cl(-), Na(+), Mg(2+), NH(4)(+) and Ca(2+)) and of 17 elements (Al, As, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, S, Se, V, Zn, Sb, Si and Ti) in two fractions-extract and residue-on the same sample of air particulate matter is described. The two-step method was tested on the SRM NIST 1648 for equivalence with two reference methods, the EMEP procedure for ions extraction and the EN 12341 standard for the elemental determination of the PM(10) and is suitable for application to small sample amounts (less than 1mg of particulate matter is needed), i.e. those collected by daily low volume filter-sampling. Performance times of the procedure were optimised to meet the target of routine application for large scale monitoring samples. A single ultrasonic-assisted extraction of air particulate matter is performed in 0.01M acetate buffer at pH 4.5, followed by IC ions analysis and ICP-OES elemental analysis of the extract and by ICP-OES elemental analysis of the mineralized residue after dissolution by microwave-assisted digestion with a HNO(3)/H(2)O(2) mixture. Using a pH buffered extracting solvent was preferred to water or diluted acid solutions to improve the reproducibility of metals extraction with respect to existing leaching methods; the influence of pH, nature and concentration of the buffer solution and extraction time on analytes concentration in the extract is discussed. Values of ions extraction and elements recoveries resulted fairly equivalent with those obtained by the reference methods. The study was also extended to some non-certified elements (Mg, S, Sb, Si and Ti) for their environmental significance. Elements recoveries were obtained as sum of the extract and residue fractions and were comparable with those obtained by direct dissolution. Standard deviations were within 10% for almost all detected ions and elements.
 ...
PMID:Determination of metals, metalloids and non-volatile ions in airborne particulate matter by a new two-step sequential leaching procedure Part A: Experimental design and optimisation. 1897 Jun 7

This is a first attempt to measure the elemental mass loading in size-segregated aerosol particles using a laser ablation ICP-MS mapping approach in combination with image analysis software. For optimal mapping of impaction spots on foils the laser ablation ICP-MS parameters resolution, sensitivity and analysis time were critically balanced, depending on the size of the particles and the mass loading. It was shown that size-segregated particles originating from industry-influenced or urban areas could be visualized (shades of gray or "pseudocolours" representing mass loading) and digitally analyzed by comparison with a commercially available air particulate SRM (NIST 2783). Actual results for industry-influenced and urban aerosol particles show distribution profiles that are similar to these obtained with a conventional wet-chemical leaching approach (with ICP-OES or ICP-MS analysis). Also the mass loadings were in the same range although with whole-spot laser ablation ICP-MS analysis even elemental concentrations in nanoparticles could be measured whereas the leaching approach had insufficient sensitivity to measure these particles. Contrary to the use of single line or crater laser ablation ICP-MS as sometimes practiced in the literature it was found essential to map whole impaction spots due to artifacts generated by cascade impactor sampling, leading to distorted impaction spots (presence of halos or satellites).
 ...
PMID:A multi-element mapping approach for size-segregated atmospheric particles using laser ablation ICP-MS combined with image analysis. 1897 27

A new test method for boric acid in agar was developed. After digestion with nitric acid, the concentration of boron was measured by ICP-AES or ICP-MS with internal standards. Collaborative studies involving 5 laboratories were conducted to evaluate the new method by using a finely powdered agar sample and a standard sample (NIST SRM SRM1570a). The repeatability and reproducibility were very good. Moreover, HORRAT(R) values were less than 2. Therefore, it was considered that the new method is acceptable for the determination of boric acid in agar.
 ...
PMID:[Development and evaluation of determination methods for boric acid in agar using ICP-AES and ICP-MS]. 1902 84

An analytical technique utilizing a near-field effect (to enhance the incident light energy on the thin tip of an Ag needle) in a laser ablation inductively coupled plasma mass spectrometry (NF-LA-ICP-MS) procedure was developed. To produce the thin needles with a tip diameter in the hundreds of nm range a robust needle etching procedure was established. The 'sample-to-tip' distance was controlled via the measurement of a tunnel current between the needle and sample surface. The NF-LA-ICP-MS technique thus developed was applied for the analysis of copper isotopic standard reference material NIST SRM 976 and tungsten-molybdenum alloy NIST SRM 480 in the nm resolution range. The observed craters ranged from 200 nm to about 2 microm in diameter and were dependent on the needle used as well as on the 'sample-to-tip' distance. The mass spectrometric measurements of (63)Cu(+) ion intensity on NIST SRM 976 showed that using near-field enhancement in laser ablation allowed a roughly 6-fold increase in the ion intensity of the analyte when the needle was about 100 nm (and below) from the surface, in contrast to when it was far away (e.g. 10 microm) from the sample. The relative standard deviation (RSD) of the (65)Cu(+)/(63)Cu(+) isotopic ratio measurements by NF-LA-ICP-MS was 3.9% (n = 9). The detection efficiencies obtained for the compared LA-ICP-MS and NF-LA-ICP-MS methods were found to be 4.6 x 10(-3) counts per second (cps)/ablated atom and 2.7 x 10(-5) cps/ablated atom, respectively.
 ...
PMID:Near-field laser ablation inductively coupled plasma mass spectrometry: a novel elemental analytical technique at the nanometer scale. 1905 Dec 33

Environmental archives like peat deposits allow for the reconstruction of both naturally and anthropogenically forced changes in the biogeochemical cycle of Pb as well as the quantification of past and present atmospheric Pb pollution. However, records of atmospheric Pb deposition from pre-industrial times are lacking. In a publication by Weiss et al. [Weiss, D., Shotyk, W., Boyle, E.A., Kramers, J.D., Appleby, P.G., Cheburkin, A.K., Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs. Sci Total Environ 2002;292:7-18]. Pb isotopes data measured by Q-ICP-MS and TIMS, concentration and enrichment data was presented for sites in eastern Canada (PeW1) and northwestern Scotland (LL7c), dating to 1586 A.D and 715 A.D., respectively. Here these same cores are re-analysed for Pb isotopes by MC-ICP-MS thereby acquiring 204Pb data and improving on the original data in terms of resolution and temporal coverage. Significant differences were found between the Q-ICP-MS/TIMS and MC-ICP-MS measurements, particularly at PeW1. These discrepancies are attributed to the problematic presence of organic matter during sample preparation and analysis complicated by the heterogeneity of the organic compounds that survived sample preparation steps. The precision and accuracy of Pb isotopes in complex matrices like peat is not always well estimated by industrial standards like NIST-SRM 981 Pb. Lead pollution histories at each site were constructed using the MC-ICP-MS data. The entire LL7c record is likely subject to anthropogenic additions. Contributions from local mining were detected in Medieval times. Later, coal use and mining in Scotland, Wales and England became important. After industrialization (ca. 1885 A.D.) contributions from Broken Hill type ores and hence, leaded petrol, dominate atmospheric Pb signatures right up to modern times. At PeW1 anthropogenic impacts are first distinguishable in the late 17th century with the mining and use of local coal. After industrialization (ca. 1810 A.D.), coal and petrol are the main Pb sources. A comprehensive estimate of the natural atmospheric background 206Pb/207Pb signature in eastern Canadian aerosols is made with a value of approximately 1.19.
 ...
PMID:Two high resolution terrestrial records of atmospheric Pb deposition from New Brunswick, Canada, and Loch Laxford, Scotland. 1906 75


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