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)

A preconcentration-separation technique for lead(II), cadmium(II), chromium(III), nickel(II) and manganese(II) ions has been established. The procedure is based on coprecipitation of these ions by the aid of Cu(II)-dibenzyldithiocarbamate precipitate. The precipitate was dissolved in 0.5 mL of concentrated HNO(3), and made up to 5 mL with distilled water. The heavy metals were determined by flame atomic absorption spectrometer. The effects of analytical parameters like pH, amounts of reagents, sample volume, etc. on the recoveries of heavy metals were investigated. The influences of matrix ions were also examined. The detection limits for the heavy metals based on 3 sigma (N=21) were found in the range of 0.34-0.87 microg L(-1). In order to validate the proposed method, two certified reference materials of NIST SRM 2711 Montana soil and NIST SRM 1515 Apple leaves were analyzed with satisfactory results. The proposed method was applied for the determination of lead, cadmium, chromium, nickel and manganese in environmental samples.
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PMID:Multi-element coprecipitation for separation and enrichment of heavy metal ions for their flame atomic absorption spectrometric determinations. 1858 57

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.
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PMID:A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry. 1862 Aug 9

Due to the consumption of chicken and chicken products in Turkey at high ratio, trace metal content of chicken and chicken products from Turkey were determined by atomic absorption spectrometry after microwave digestion. The accuracy of the method was confirmed by analysis of standard reference material (NIST SRM 1577b Bovine liver). Trace element content in various parts of chicken samples and chicken products were to be in the range of 0.10-114 microg/g for copper, 0.25-6.09 microg/kg for cadmium, 0.01-0.40 microg/g for lead, 0.10-0.91 microg/g for selenium, 0.05-3.91 microg/g for manganese, 0.06-0.10 microg/g for arsenic, 0.01-0.72 microg/g for chromium, 0.01-2.08 microg/g for nickel, 0.01-0.02 microg/g for cobalt, 0.10-1.90 microg/g for aluminium, 1.21-24.3 microg/g for zinc, 2.91-155 microg/g for iron. The levels of lead in some analyzed chicken products were higher than the recommended legal limits for human consumption.
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PMID:Assessment of trace element contents of chicken products from Turkey. 1875 93

In this paper is proposed a simultaneous pre-concentration procedure using cloud point extraction for the determination of copper and zinc in food samples employing sequential multi-element flame atomic absorption spectrometry (FS-FAAS). The reagent used is 1-(2-pyridylazo)-2-naphthol (PAN) and the micellar phase is obtained using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) and centrifugation. The optimization step was performed using Box-Behnken design for three factors: solution pH, reagent concentration and buffer concentration. A multiple response function was established in order to get an experimental condition for simultaneous extraction of copper and zinc. Under the optimized experimental conditions, the method allows the determination of copper with a limit of detection (3sigma(b)/S, LOD) of 0.1 microg L(-1), precision expressed as relative standard deviation (R.S.D.) of 2.1 and 1.3% (N=10), for copper concentrations of 10 and 50 microg L(-1), respectively. Zinc is determined with a LOD of 0.15 microg L(-1) and precision as R.S.D. of 2.7 and 1.7% for concentrations of 10 and 50 microg L(-1), respectively. The enhancement factors obtained were 36 and 32 for copper and zinc, respectively. The accuracy was assessed by analysis of certified reference materials, namely, SRM 1567a - Wheat Flour and SRM 8433 - Corn Bran from National Institute of Standards & Technology and BCR 189-wholemeal flour from Institute of Reference Materials and Measurements. The method was applied to the determination of copper and zinc in oats, powdered chocolate, corn flour and wheat flour samples. The copper content in the samples analyzed varied from 1.14 to 3.28 microg g(-1) and zinc from 8.7 to 22.9 microg g(-1).
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PMID:Pre-concentration procedure for determination of copper and zinc in food samples by sequential multi-element flame atomic absorption spectrometry. 1880 1

An efficient wet digestion method is described which allows the determination of various elements in animal tissues. Copper, iron, manganese, lead and cadmium in one dilution of the digested sample can be determined by means of graphite-furnace atomic-absorption spectrometry, with Zeeman background correction. Tests with the National Bureau of Standards Bovine Liver SRM as reference gave analytical results, obtained with calibration graphs as well as by the standard-addition method, which agreed well with the certified values.
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PMID:Determination of copper, iron, manganese, lead and cadmium in automatically wet-digested animal tissue by graphite-furnace atomic-absorption spectrometry with zeeman background correction. 1896 64

Cadmium, lead and copper were determined in synthetic sea-water, drinking water and the NBS 1643b Trace Elements in Water standard reference material at mug/l. levels by flame atomic-absorption spectrometry after on-line preconcentration by sorbent extraction with a flow-injection system. Bonded silica with octadecyl functional groups packed in a micro column of 100 mul capacity was used to collect diethylammonium diethyldithiocarbamate complexes of the heavy metals in the aqueous samples. The sample loading time was 20 sec at a flow-rate of 3.3 ml/min. Ethanol or methanol was used to elute the adsorbed analytes into the spectrometer. The sample loading rate, elution rate and pH were optimized. Enrichment factors of 19-25 for Cd, Pb and Cu were achieved at sampling frequencies of 120/hr with precisions of 1.4, 1.0 and 1.3% rsd (n = 11), respectively. The detection limits (3sigma) for Cd, Pb and Cu were 0.3, 3 and 0.2 mug/l., respectively. Determination of Cd, Pb and Cu in NBS SRM 1643b showed good agreement with the certified values. Recoveries of Cd and Pb added to sea-water were 95 and 102%, respectively.
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PMID:Determination of cadmium, lead and copper in water samples by flame atomic-absorption spectrometry with preconcentration by flow-injection on-line sorbent extraction. 1896 93

The stability constants of the complexes of glycinate ion with copper(II), nickel(II) and hydrogen(I) and of nitrilotriacetate ion with calcium(II) and hydrogen(I) and the ionic product of water (K(w)) were determined potentiometrically. The measurements were carried out at 25.0 degrees C in four different ionic strengths up to I (= I(c)) = 2.50 and two different ionic media (KNO(3) and (CH(3))(4)NNO(3)). Extrapolation of equilibrium constants to zero ionic strength and ionic strength corrections to equilibrium constants were carried out with the data obtained from both media using the TEC (thermodynamic equilibrium constant) equation and computer program. The constants of the potassium complexes with nitrilotriacetic acid at low ionic strength are also given. Successful attempts to predict equilibrium constants for other ionic media using TEC parameters and the procedure of the specific ion-interaction theory (SIT) are given. The variations of equilibrium constants with the ionic strengths and ionic media are demonstrated.
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PMID:Extrapolation of molar equilibrium constants to zero ionic strength and parameters dependent on it. Copper(II), nickel(II), hydrogen(I) complexes with glycinate ion and calcium(II), hydrogen(I) complexes with nitrilotriacetate ion. 1896 30

A simple flow injection on-line dilution procedure with detection by inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of copper, zinc, arsenic, lead, selenium, nickel and molybdenum in human urine. Matrix effects were minimized by employing a dilution factor of 16.5 with on-line standard addition, and (103)Rh was used as internal standard to compensate for signal fluctuation. The procedure was validated by the analysis of two standard reference materials SRM 2670 (NIST) and Seronormtrade mark Trace Elements in Urine. Recovery experiments were performed by spiking the reference materials as well as artificial urine. The detection limits (mug l(-1)) were 0.12,0.96,0.30,0.09,0.45,0.08,0.09, and the precisions (RSD,%) were 2.6,2.3,3.0,3.7,3.7,4.9,2.8 for Cu, Zn, As, Pb, Se, Ni and Mo, respectively. The procedure was applied to the analysis of 41 human urine samples. No correlations between the concentrations of the elements were observed.
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PMID:Flow injection on-line dilution for multi-element determination in human urine with detection by inductively coupled plasma mass spectrometry. 1896 53

This paper shows the influence of different sample storage protocols, on the chemiluminescence signal of some metal ions. The storage protocols studied were: acid addition (HCl or HNO(3)) and no reagent addition to filtered and refrigerated (T=4 degrees C) samples. Light emission was produced for the chemiluminescence reaction between luminol and hydrogen peroxide in buffer carbonate conditions (pH 10.8) catalysed by Cr(III), Co(II) and Cu(II). Batch and/or flow modes in different conditions were tested. Fe(II), Fe(III), Ni(II) and Mn(II) did not give chemiluminescence in the studied conditions. A parallel study of sensitivity and selectivity was performed. Then the presence or absence of the masking agent EDTA, added to samples or used in the carrier stream, is assayed. If the samples are acidified with HNO(3), a previous neutralisation is needed using batch mode. The determination of Cr(III) is independent of storage protocol by flow injection (FI) method; however, the determination of Co(II) or Cu(II) or total determination of three metals requires the conditioning of standards. Detection limits achieved are ranged between 0.5 and 2 mug l(-1). For batch mode, detection limits are better for unacidified samples and worse for carbonate-neutralised samples. The influence of storage protocols was validated using standard metal mixtures and calibration solutions. The use of standard reference material (SRM(c) 1640) (Trace elements in natural water) corroborates the previous statements and validates the accuracy of the different approaches underlined. This paper demonstrates that it is possible to determine Cr(III) selectively in natural waters.
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PMID:Influence of water sample storage protocols in chemiluminescence detection of trace elements. 1896 48

A polyethylene glycol (PEG)-based aqueous two-phase system has been established for the extraction of Ni-dimethylglyoximato complex. Appropriate amounts of PEG solution and solid (NH(4))(2)SO(4) were added to the Ni-dimethylglyoximato complex which had been formed in the presence of sodium tartrate and K(2)S(2)O(8) at pH 12 in a separatory funnel and shaken vigorously for about 1min. The mixture was allowed to stand for 10min and then the absorbance of the extracted complex in the upper PEG-rich phase was measured at 470nm. Beer's law was obeyed over the range of 0.26-2.1ppm Ni. The proposed extraction method has been applied to the determination of Ni in steel. A steel sample was decomposed with an appropriate acid mixture. An aliquot of the sample solution was taken, treated with H(3)PO(4) and most of the iron and copper were removed by hydroxide precipitation using solid BaCO(3) to control the pH of the sample solution in advance of the extraction of Ni. The analytical results obtained for Ni in steel certified reference material JSS 650-10 (The Japan Iron and Steel Federation), BCS 323 (Bureau of Analysed Samples Ltd.) and NIST SRM 361 and 362 (National Institute of Standards and Technology) were in good agreement with certified values.
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PMID:Aqueous two-phase extraction of nickel dimethylglyoximato complex and its application to spectrophotometric determination of nickel in stainless steel. 1896 59


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