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The capability of LA-ICP-MS for determination of trace impurities in transparent quartz glasses was investigated. Due to low or completely lacking absorption of laser radiation, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) proves difficult on transparent solids, and in particular the quantification of measurement results is problematic in these circumstances. Quartz glass reference materials of various compositions were studied by using a Nd:YAG laser system with focused laser radiation of wavelengths of 1064 nm, 532 nm and 266 nm, and an ICP-QMS (Elan 6000, Perkin Elmer). The influence of ICP and laser ablation conditions in the analysis of quartz glasses of different compositions was investigated, with the laser power density in the region of interaction between laser radiation and solid surface determining the ablation process. The trace element concentration was determined via calibration curves recorded with the aid of quartz glass reference materials. Under optimized measuring conditions the correlation coefficients of the calibration curves are in the range of 0.9-1. The relative sensitivity factors of the trace elements determined in the quartz glass matrix are 0.1-10 for most of the trace elements studied by LA-ICP-MS. The detection limits of the trace elements in quartz glass are in the low ng/g to pg/g range.
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PMID:Studies of LA-ICP-MS on quartz glasses at different wavelengths of a Nd:YAG laser. 1149 98

A modified graphite furnace for solid-sampling atomic absorption spectrometry as an electrothermal vaporizer (ETV) was coupled to a Perkin-Elmer/Sciex ELAN 6000 ICP mass spectrometer. The integrals obtained from electrothermal vaporization of aliquots containing As, Cd, Cu, Co, Fe, Mn, Pb, Se, and Zn were compared with those obtained from pneumatic nebulization of the same aqueous standard solution. The pneumatic nebulizer was calibrated by weighing the mass of aqueous aerosol trapped on a filter. With "wet plasma" conditions maintained also for measurements with the ETV and reference signals for analyte signals obtained with the calibrated pneumatic nebulization, the transport efficiency of the ETV system, e.g. the ratio of the analyte amount introduced into the plasma to that amount dosed into the vaporizer, was determined. The transport efficiency of two different tube and interface designs has been evaluated. Investigations with and without the use of trifluoromethane as reactive gas, with different furnace heating rates, and with varying gas flows were performed. In general, the tube equipped with a nozzle led to generally higher transport efficiency than the standard tube. Without trifluoromethane transport efficiencies ranged from 10% to 35% with the standard tube and from 15% to 50% with the nozzle-type tube. With addition of 2 mL min(-1) trifluoromethane to the argon flow of 400 mL min(-1) through the tube, transport efficiencies from 20% to 70% and from 70% to 100% were achieved with the standard and nozzle-type tubes, respectively.
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PMID:Analyte transport efficiencies in electrothermal vaporization for inductively coupled plasma mass spectrometry. 1156 62

Reliable trace metal analysis of environmental samples is dependent upon the availability of high accuracy, matrix reference standards. Here, we present Cd, Cu, Ni, Pb and Zn isotope dilution determination for an estuary water certified reference material (LGC 6016). This work highlights the need for high-accuracy techniques in the development of trace element CRMs rather than conventional inter-laboratory trials. Certification of the estuary water LGC6016 was initially determined from a consensus mean from 14 laboratories but this was found to be unsatisfactory due to the large discrepancies in the reported concentrations. The material was re-analysed using isotope dilution ICP-MS techniques. Pb and Cd were determined using a conventional quadrupole ICP-MS (Elan 5000). Cu, Zn and Ni were determined using a magnetic sector ICP-MS (Finnigan Element), which allowed significant polyatomic interferences to be overcome. Using the magnetic sector instrument, precise mass calibration to within 0.02 amu permitted identification of the interferences. Most interferences derived from the sample matrix. For example, the high Na content causes interferences on 63Cu, due to the formation of 40Ar23Na and 23Na2 16O1H, which in a conventional quadrupole instrument would relate to an erroneous increase in signal intensity by up to 20%. For each analyte a combined uncertainty calculation was performed following the Eurachem/GTAC and ISO guideline. For each element a combined uncertainty of 2-3% was found, which represents a 10-fold improvement compared to certification by inter-laboratory comparison. Analysis of the combined uncertainty budget indicates that the majority of systematic uncertainty derives from the instrumental isotope ratio measurements.
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PMID:High resolution ID-ICP-MS certification of an estuary water reference material (LGC 6016) and analysis of matrix induced polyatomic interferences. 1169 13

Large volume fjord and seawater samples have been radiochemically prepared for ICP-MS analysis in order to test the robustness of the procedure and to carry out a comparison of two ICP-MS set-ups. A sector field instrument (MicroMass PT2) coupled with an ultrasonic nebuliser and a quadrupole ICP-MS (Perkin-Elmer Elan 6000) coupled with an electrothermal vaporisation (ETV) unit were used. The results showed that the radiochemical procedure was robust, removing Ru and Mo to acceptable levels, and that the two set-ups gave results that were in agreement. The correlation coefficient between the sets of 11 results was 1.0 +/- 0.05. The importance of establishing the matrix effect when using an ETV is discussed.
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PMID:Comparison of two ICP-MS set-ups for measuring 99Tc in large volume water samples. 1182 99

Condensation reactions in the bandpass reaction cell or dynamic reaction cell (DRC) were used for the determination of actinides and lanthanides such as uranium, thorium, neodymium and praseodymium. These elements react with oxygen reagent gas in the dynamic reaction cell of the ELAN DRC II instrument to give mono- and/or dioxo cationic species (UO(2)+, ThO+, NdO+ and PrO+, respectively). Increasing the oxygen flow rate in the dynamic reaction cell leads to the rapid decrease of the singly charged metal ions accompanied by the fast increase in the intensity of the oxide ion. This phenomenon is used to improve considerably the sensitivity of ICP-MS instruments equipped with a dynamic reaction cell for actinides and lanthanides. Estimated detection limits (EDL) obtained in this work for uranium, thorium, neodymium-144 and praseodymium are 0.022, 1.0, 0.045, and 0.10 ng L(-1), respectively. The detection limit for uranium measured in the standard (vented) mode of an ELAN DRC II was found to be 0.22 ng L(-1), which is an order of magnitude higher compared to the pressurized mode.
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PMID:Condensation reaction in the bandpass reaction cell improves sensitivity for uranium, thorium, neodymium and praseodymium measurements. 1285

Ten tumor tissue and normal tissue around tumors were collected from the patients with lung cancer. After digested by mixed acids(HNO3:HClO4 = 10:1), 15 rare-earth elements (REEs) in the tissue were measured directly by ELAN 5000 ICP-MS. Tissue levels and distribution of 15 REEs were analyzed and compared with those in healthy human lung tissue measured in the same condition. Re (rhenium) was used as an internal standard element to compensate for matrit inhibition and sensitivity drift. Recoveries of standard addition for REEs was 92.9%-111.3% and the precision was 0.96%-3.07%. Results showed that levels of 15 REEs in normal tissues around the tumor was as 2.07-2.51 times high as those in the tumor tissue, while the REE distribution curves of them was similar. There were positive abnormalities of Ce and negative abnormalities of Eu in REE curves of both tissue after chondrite-normalized. Compared REE level and distribution pattern in normal tissue with those in tumor tissue from patients with lung cancer, it was found that contents of light REE in lung tissue of health human were much higher while the contents of media and heavy REE were much lower. LREE/HREE in the tumor tissue and normal tissue with lung cancer and health human lung tissue were 12.99, 13.72 and 44.11 respectively. This study suggested that there might be light REEs accumulation in human lung tissue compared with REE distribution in the air particulates and soil. Light REEs accumulation in the lung of healthy people was more obviously than that in patients with lung cancer.
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PMID:[Levels and distribution of 15 rare earth elements in tumor and normal lung tissue from the patients with lung cancer]. 1465 Jan 79

Ongoing discussions about the origin of elemental fractionation occurring during LA-ICP-MS analysis show that this problem is still far from being well understood. It is becoming accepted that all three possible sources (ablation, transport, excitation) contribute to elemental fractionation. However, experimental data about the vaporisation size limit of different particles in the ICP, as produced in laser ablation, have not been available until now. This information should allow one to determine the signal contributing mass within the ICP and would further clarify demands on suitable laser ablation systems and gas atmospheres in terms of their particle size distribution. The results presented here show a vaporisation size limit of laser induced particles, which was found at particle sizes between 90 nm and 150 nm using an Elan 6000 ICP-MS. Due to the fact that the ICP-MS response was used as evaluation parameter, vaporisation and ionisation limits are not distinguishable. The upper limit was determined by successively removing the larger particles from the aerosol, which was created by ablation of a NIST 610 glass standard at a wavelength of 266 nm, using a recently developed particle separation device. Various particle fractions were separated from the aerosol entering the ICP. The decrease in signal intensity is not proportional to the decrease in volume, indicating that particles above 150 nm in diameter are not completely ionised in the ICP. Due to the limited removal range of the particle separation device, which cannot remove particles smaller than 150 nm, single hole ablations were used to determine the lower vaporisation limit. This is based on measurements showing that larger particles occur dominantly during the first 100 laser pulses only. After this period, the ratio of ICP-MS counts and total particle volume was found to be constant while most of the particles are smaller than 90 nm, indicating complete vaporisation and ionisation of these particles. To describe the influence of different plasma forward powers on the vaporisation limit, the range 1000-1600 W was studied. Results indicate that optimum vaporisation and ionisation occurs at 1300 W. However, an increase of the particle ionisation limit towards larger particles was not observed within the accuracy of this study using the full range of parameters available for optimisation on commonly used ICP-MS instruments.
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PMID:Size-related vaporisation and ionisation of laser-induced glass particles in the inductively coupled plasma. 1465 26

The use of laser ablation inductively coupled mass spectrometry (laser ICP-MS), in combination with a calibration procedure involving the addition of enriched isotopes, for the determination of trace elements in birch leaves and their ashes is described. Samples are pressed into pellets without binder materials and analyzed using the ICP-MS spectrometer ELAN 5000 with the laser sampler type 320 (Perkin Elmer). The analytical results obtained by two methods are compared with the values obtained after digestion of the same samples and analysis of the resulting solutions by ICP-MS. The results are discussed in terms of precision, accuracy and limits of detections.
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PMID:Analysis of leaves by using the laser ICP-MS with isotope dissolution method. 1504 90

ICP-mass spectrometer Perkin Elmer Elan 6000 was adapted for ETV analysis by coupling with GBC GF 3000 graphite furnace atomiser. Both instruments were connected by a 25 cm long PTFE tubing of 6 mm i.d. and a custom-made interface. The apparatus was applied to nickel determination using isotope dilution technique. The efficiency of analyte transfer through the interface was approximately 20%, however the incomplete transfer did not influence the blank values. Measured isotope ratio was very stable, whereas the magnitude of ion signal showed a little shift. CRM samples were analysed after microwave decomposition and by slurry technique as well. Obtained results were compared with those of pneumatic sample nebulisation after nickel separation on Chelex column. All tested techniques gave accurate results with comparable precision. However, the slurry technique allowed significant decreasing of the blank values and the limit of detection. The duration of analysis run can also be substantially shortened from several hours to a few minutes.
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PMID:Custom-made interface between electrothermal vaporiser and inductively coupled plasma-mass spectrometer: determination of nickel by isotope dilution in plant samples. 1896 5

A robust analytical method has been developed and validated by use of high-performance liquid chromatography inductively coupled plasma mass spectrometry with Dynamic Reaction Cell (DRC) technology that separates seven arsenic (As) species in human urine: arsenobetaine (AB), arsenocholine, trimethylarsine oxide (TMAO), arsenate (As(V)), arsenite (As(III)), monomethylarsonate, and dimethylarsinate. A polymeric anion-exchange (Hamilton PRP X-100) column was used for separation of the species that were detected at m/z 75 by ICP-DRC-MS (PerkinElmer SCIEX ELAN DRCII) using 10% hydrogen-90% argon as the DRC gas. The internal standard (As) is added postcolumn via an external injector with a sample loop. All analyte peaks were baseline-separated except AB and TMAO. Analytical method limits of detection for the various species ranged from 0.4 to 1.7 microg L(-1) as elemental As. As(III) conversion to As(V) was avoided by adjusting the urine sample to <pH 6. Analyses of the National Institute of Standards and Technology standard reference material (SRM) 2670 and 2670a elevated and National Institute for Environmental Studies certified reference material (CRM) no. 18 for arsenic species yielded results within the certified SRM-CRM limits for As species; likewise, the sum of all species compared favorably to SRM 2670 and 2670a target values for total As. This As speciation method is now being used in a production mode for the analysis of a US population survey, the National Health and Nutrition Examination Survey, as well as for other biomonitoring studies of As exposure. This method meets our requirement for sample throughput of 2,000-3,000 sample analyses per year.
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PMID:Determination of seven arsenic compounds in urine by HPLC-ICP-DRC-MS: a CDC population biomonitoring method. 1908 83


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