Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The quantification of trace elements in used lubricating oil is useful for evaluating the wearing of specific components of engines. In the present work, inductively coupled plasma optical emission spectrometry (ICPOES) was used for determining five refractory elements (Ni, Mo, Cr, V and Ti) in lubricating-oil samples. The methodology was developed while aiming at the introduction of such organic samples into the ICP as emulsions. Several nebulization systems were tested with clear advantage for Meinhard K3 coupled with a cyclonic spray chamber. The carbon deposition on the injector tip as well as the plasma background was minimized through careful optimization of the Ar and O2 gas mixture flows into the plasma. The optimization of instrumental and experimental parameters allowed quantification using calibration curves prepared with analyte inorganic standards. An internal standard (Sc) was used to correct the matrix effects and signal fluctuations. The limits of detection (3Sb/m), in the ng g(-1) range were obtained for all five elements. The methodology was validated through an analysis of standard reference materials (SRM 1084a, 1085a and 1085b). Good analyte recoveries (from 92.6 to 104.7%) were achieved. Comparison studies against established ICPOES methodologies (sample acid decomposition or sample direct dilution in an organic solvent) have shown that the proposed methodology present clear advantages in terms of simplicity of sample preparation, overall analysis time, and the use of inorganic standards for calibration instead of expensive metallorganic standards.
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PMID:Determination of refractory elements in used lubricating oil by ICPOES employing emulsified sample introduction and calibration with inorganic standards. 1505 65

The abilities of various extractants to recover four arsenic species [As(iii), As(v), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA)] from soils spiked with 20 micro g g(-1) As were investigated. The extractants were water, buffer solutions (citrate and ammonium dihydrogen phosphate), acidic solutions (phosphoric acid and acetic acid), a basic solution (sodium hydroxide) and household chemicals (vinegar and Coca Cola). Gentle shaking at room temperature with each extractant for 24 h gave different recoveries for the different arsenic species. With 0.1 M NaOH solution 46% As(iii), 53% DMA, 100% MMA and 84% As(v) were recovered. A rapid extraction procedure using a sonicator probe has been developed to obtain higher extraction efficiencies. Extracts of arsenic-spiked soil, SRM 2711 Montana soil and SRM 2709 San Joaquin soil were analyzed by HPLC-ICP-MS. In the SRM water extracts, DMA and MMA were identified in addition to inorganic arsenic. The solution detection limits (3s) were 0.1, 0.12, 0.13 and 0.15 ng mL(-1) for As(iii), DMA, MMA and As(v), respectively for HPLC-ICP-MS.
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PMID:Extraction of arsenic species from spiked soils and standard reference materials. 1528 14

Cd, Cr, Cu and Ni were determined in two different species of woodlice: Porcellio scaber and Porcellio dilatatus. Both P. scaber and P. dilatatus were cultivated under standardized conditions in a climatic chamber. Moreover, skins of the cultivated animals were collected and analysed separately to examine whether moulting is a way of detoxification from these elements. After drying and grinding both animal and skin samples, they were pooled to obtain enough sample material for each species. The pooled samples were digested in pure concentrated nitric acid using microwave-assisted high pressure digestion and, finally, analysed by ICP-OES. Special emphasis was given to quality control. To match the matrix of the samples very closely, the reference materials Dorm-2, Dogfish Muscle (Squalus acanthias) and SRM 1577b Bovine Liver were used to evaluate the whole analytical process including sample digestion. Analyses of the elements in the reference materials were carried out using three different wavelengths for each element simultaneously to check for spectral interferences and to select the wavelengths which were best suited for the analyses. Concentrations of Cd, Cr, Cu and Ni in woodlice and their skins indicated that moulting is a possible means of detoxification in the case of Cr and Ni.
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PMID:Accurate determination of Cd, Cr, Cu and Ni in woodlice and their skins--is moulting a means of detoxification? 1562 81

This paper studied the trace elements Cs, Th and U in ten kinds of human autopsy tissues by ICP-MS. The instrumental operating conditions were optimized for the measurement of Cs, Th and U. Rhodium (Rh) was used as an internal standard element to compensate matrix effect. Detection limits for Th, U and Cs were 5.7-17.8 pg x mL(-1). The recoveries for spiking liver samples were 96%-107%, and their RSDs were 4.8%-8.9%. Reference materials of NIST SRM 8414 Bovine and NIST SRM 1486 Bone Meal were analyzed by the described method, and the analytical results agreed well with the reference values. Human autopsy tissues samples were digested by mixed acid (HNO3 + HClO4). The determination of Cs, Th and U in lung, liver, bone, heart, stomach, spleen, muscle, kidney, thyroid gland and intestinum tenue was performed by ICP-MS without separation and enrichment procedures. The obtained results indicated that this method is rapid, sensitive and accurate; the distribution of the three elements is different from one to another human organ sample; the main organ targets for Th and U are lungs and kidneys; and a coordinated variation of Cs, Th and U concentration in lungs was found in the samples collected from Hebei and Sichuan provinces.
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PMID:[Determination of trace Cs, Th and U in ten kinds of human autopsy tissues by ICP-MS]. 1576 38

A method has been developed enabling direct analysis (i.e. after dilution only) of beer, instant coffee, milk, and milk powder by ICP-AES. Analysis of the beverages after dilution with a low concentration of HNO3 was used for accurate determination of essential minor and trace elements (Ca, Mg, K, P, S, and Zn). Selenium, introduced as the hydride, was determined simultaneously with the other non-hydride-forming elements using the commercial multi-mode sample-introduction system (MSIS). To obtain accurate results, however, some simple pre-treatment was needed. Analysis was also performed after microwave-assisted decomposition of the samples. Three different modes of sample-preparation, i.e. dilution only, partial decomposition (aqua regia treatment), and complete decomposition were compared. The results obtained by use of the three different sample-preparation methods were in very good agreement. Results from analysis of certified reference material (SRM 1459 non-fat milk powder) also verified the accuracy of the methods. The limit of detection obtained for Se using dual-mode sample introduction was 0.5 ng mL(-1), which corresponds to approximately 2 ng g(-1) in beer and approximately 4 ng g(-1) in coffee and milk when using the recommended procedure.
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PMID:Simultaneous determination of hydride (Se) and non-hydride-forming (Ca, Mg, K, P, S and Zn) elements in various beverages (beer, coffee, and milk), with minimum sample preparation, by ICP-AES and use of a dual-mode sample-introduction system. 1590 Apr 68

Fundamental understanding of aerosol formation and particle transport are important aspects of understanding and improving laser-ablation ICP-MS. To obtain more information about particles entering the ICP, laser aerosols generated under different ablation conditions were collected on membrane filters. The particles and agglomerates were then visualised using scanning electron microscope (SEM) imaging. To determine variations between different sample matrices, opaque (USGS BCR-2G) and transparent (NIST SRM 610) glass, CaF(2), and brass (MBH B26) samples were ablated using two different laser wavelengths, 193 and 266 nm. This study showed that the condensed nano-particles ( approximately 10 nm in diameter) formed by laser ablation reach the ICP as micron-sized agglomerates; this is apparent from filters which contain only a few well-separated particles and particle agglomerates. Ablation experiments on different metals and non-metals show that the structure of the agglomerates is matrix-dependent. Laser aerosols generated from silicates and metals form linear agglomerates whereas particle-agglomerates of ablated CaF(2) have cotton-like structures. Amongst other conditions, this study shows that the absorption characteristics of the sample and the laser wavelength determine the production of micron-sized spherical particles formed by liquid droplet ejection.
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PMID:The agglomeration state of nanosecond laser-generated aerosol particles entering the ICP. 1613 49

Arsenic speciation analysis suffers in general from high sample handling time required by sample preparation. In a previous work, ultrasonic probe has been proved to reduce sample treatment time for arsenic extraction in rice to only a few minutes. Base upon the obtained results, here several extraction media for chicken, fish and soil samples (SEAS G6RD-CT2001-00473) have been studied and evaluated employing the same technique. Chicken sample needed an enzymatic treatment in order to liberate the species linked to the protein matrix. Extraction of the major species in fish, AsB, was quantitatively achieved in water in 1 min. Also 1 min was enough to leach about 85% of species present in soils and sediments, mainly the inorganic ones, using H(3)PO(4). In all cases, no inter-conversion among As species was observed. The five species found in those samples were separated using an improved HPLC-ICP-MS method in only 11 min, with detection limits at the ng l(-1) level. The proposed methods were validated by analysing several Certified Reference Materials: SRM 1,568 a rice flour, CRM-627 tuna fish tissue, SOIL-7 soil and MURST-ISS-A1 Antarctic sediment.
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PMID:Evaluation of a focused sonication probe for arsenic speciation in environmental and biological samples. 1629 79

The modified BCR three step sequential extraction procedure has been applied to homogenized urban dust samples collected in sedimentation chambers of two Prague tunnels (road, Letna, subway, and station Museum), and to SRM 1648 urban particulate matter (NIST) to validate the applicability of the procedure. Analyte concentrations in the fourth step were calculated from the total content of analytes determined and verified before, in case of the SRM 1648 certified values have been utilized. Concentrations of chosen elements As, Cd, Cr, Mn, Ni, Pb, Zn (Cu, Fe) in each fraction were measured by ICP-OES and GF AAS (arsenic determination) methods. The work has been focused on (i) levels investigation of toxic elements in dust samples and their distribution following a three-stage sequential extraction procedure, (ii) finding differences between two tunnel samples utilizing the estimation of mobility of trace elements, some macro-component comparisons and main mineralogical phases determinations by XRD analysis, (iii) validation of the proposed procedure using SRM 1648 Urban Particulate Matter (NIST) and comparative data obtained by a capillary electrophoresis (CE) method.
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PMID:Mobility assessment and validation of toxic elements in tunnel dust samples--subway and road using sequential chemical extraction and ICP-OES/GF AAS measurements. 1636 87

Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes.
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PMID:Development and evaluation of a standard method for the quantitative determination of elements in float glass samples by LA-ICP-MS. 1638 27

The certification of Standard Reference Material (SRM is a registered trademark of NIST) 3103a As Spectrometric Solution is based on the gravimetric preparation value that is verified by inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. A disagreement between the gravimetric and the spectrometric values for a batch of As calibration solutions led to the discovery that the solutions contained a mixture of trivalent and pentavalent As species and that the pentavalent species was approximately 8% more sensitive than the trivalent species with ICP-OES determination. The kinetics of the reaction between As metal and nitric acid were studied, and the results were applied to develop a procedure that would consistently produce single-species pentavalent As standards, which eliminates As speciation as a source of measurement bias in the SRM certification process.
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PMID:Effect of valence state on ICP-OES value assignment of SRM 3103a arsenic spectrometric solution. 1650 19


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