Showing papers in "Analytical Sciences in 1990"

Multielement Analysis of Rocks with the Use of Geological Certified Reference Material by Inductively Coupled Plasma Mass Spectrometry

Abstract: A multielement analysis in rocks, based on inductively coupled plasma mass spectrometry, is described. Major interferences observed were the background signals for P, K, Mn, Fe and the doubly charged and oxide ions for Ni, Cu, Zn, Ga, Eu, Tb, Yb, Lu. Both geological certified reference material JB-1 as standard and indium internal standard were used to correct the matrix effect; 49 major and minor elements in rocks were determined successfully by using this method.

Characterization of potassium-selective optode membranes based on neutral ionophores and application in human blood plasma.

Abstract: Plasticized PVC membranes incorporating conventional potassium-selective neutral ionophores and a neutral H+- selective chromoionophore have been used as reversible sensing devices for an optical determination of K+ activities in pH-buffered solutions. Dynamic range, reproducibility, response time, and selectivity of the new optode membranes are discussed. With this potassium-selective membrane, the reversible optical determination of total K+ concentration in human blood plasma is available. Results are compared to measurements with ion selective electrodes and flame photometry.

Application of Inductively Coupled Plasma Mass Spectrometry to the Measurement of Long-Lived Radionuclides in Environmental Samples A Review

Abstract: This review describes applications of inductively coupled plasma mass spectrometry (ICP-MS) to the determination of long-lived radionuclides in environmental samples. Simultaneous determination of 232Th and 238U in biological samples is described in detail; in this procedure an internal standard, Tl or Bi, is adopted for correction of the matrix effect. Determination of 237Np in soil samples by ICP-MS is also described. It is chemically separated to ensure no interference from matrix elements. The detection limits are several mBq (several pg) for the case of radionuclides having a half life of thirty or forty thousand years.

Determination of Nickel, Copper, Zinc, Silver, Cadmium and Lead in Seawater by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

Abstract: Les metaux a analyser sont complexes par la dithizone et extraits dans le chloroforme avant d'etre doses par ICP couple a un spectrometre de masse. Les teneurs dosees sont de l'ordre du ng

Analytical chemistry of polythionates and thiosulfate. A review.

Abstract: The reaction of hydrogen sulfide with sulfur dioxide in aqueous solution yields Wackenroder′s solution, which contains polythionates (SxO62-: x=3, 4 and 5) and thiosulfate Various reactions of polythionates with such reagents as sulfite, cyanide, sulfide, permanganate and others are reviewed, in which the thiosulfate and/or thiocyanate formed by these reactions of polythionates are measured titrimetrically, spectrophotometrically and coulometrically As a result, simultaneous equations can be obtained through corresponding different procedures and can be used for the determination of polythionates in their mixtures with other sulfur anions Furthermore, modern liquid chromatography is described for the separation of polythionates and thiosulfate, in which quite different chromatographic techniques and conditions were employed

Chemiluminescence Analyses of Biological Constituents Using Metal-Complex Catalysts A Review

Abstract: Chemiluminescence analyses of biological constituents using metal-complex catalysts developed in our laboratory are reviewed. This study was carried out in the fields of immunoassay and high performance liquid chromatography, with special reference to the determination of micro amounts of protein. The use of a synthesized metal-complex compound instead of natural substances as a catalyst was proposed in order to make immunoassay inexpensive and reproducible, as well as to make labeling easy. The immunoassay established by the use of a fiber-optic immunosensor could be successfully applied to the determination of micro amounts of protein. The method using the activity lowering of a chemiluminescence catalyst was also established for the development of a new detection system, which was applied to both indirect and direct flow injection analyses of protein. Each chemiluminescence system was utilized for indirect and direct flow injection analyses, respectively. The direct flow injection analysis, in which a protein solution was directly injected into a flow injection system, could be used to determine the protein content more easily, rapidly, and sensitively than the indirect one. Finally, the future prospect is briefly presented regarding the present subject.

Determination of ammonium and other major cations in river and rain water by ion chromatography using silica gel as an ion exchanger.

Abstract: The separation of NH4+ from Na+, K+, Mg2+ and Ca2+ on silica gel columns was investigated using natural water samples and lithium oxalate as a retention modifier. The pore size of silica gels was found to be the most important factor affecting the retention of the cations. When a 0.0025mol dm-3 lithium oxalate solution of pH 7 was used as the mobile phase these cations could be completely separated on a short silica-gel column (Develosil 30-3, 35mm×4.0 mm i.d.) within about 20min. NH4+ contents in river (0.01-0.27ppm) and rain (1-1.8ppm) water samples were determined successfully.

Biosensor Development with a Glutamate Receptor Ion-Channel Reconstituted in a Lipid Bilayer

Abstract: A glutamate receptor ion channel (RIC) protein, isolated and purified from rat brains, was reconstituted into artificial bilayer lipid membranes. This RIC protein was found to serve as a recognition site for a sensitive detection of L-glutamate. Two types of RIC sensors were tested. When the RIC was reconstituted as a single protein in a patch-clamp membrane configuration, digital "off/on" signals were obtained for L-glutamate. With multiple proteins as a multi-channel sensor, the integrated do signals were related to the glutamate concentration. The results from these two configurations are further discussed in terms of signal amplification and concentration dependence of the sensor.

Hydride Generation Atomic Absorption Determination of Tellurium Species in Environmental Samples with in Situ Concentration in a Graphite Furnace

Abstract: An ultrasensitive method is described for the measurement of picogram amounts of tellurium species in environmental samples. The method involves selective Te(IV) reduction by sodium borohydride to hydrogen telluride, trapping in situ in a modified graphite furnace, and subsequent atomic absorption detection. The total amount of Te is determined after Te(VI) reduction to Te(IV) by boiling in hydrochloric acid. The difference between the amounts of Te(IV) and total-Te is taken as the amount of Te(VI). The absolute detection limit ranges from 2 to 4pg of tellurium. The precision of the method is 5.1% for 20pg and 2.5% for 200pg of tellurium. Analytical results are presented for natural waters, aerosol particles, geological and biological materials.

High-Performance Frontal Analysis for the Determination of the Free Drug Concentration in Protein Binding Equilibrium Using Porous Polymer Stationary Phase

Abstract: A high-performance frontal analysis method using a polyvinyl alcohol gel as a stationary phase has been developed for the determination of the free concentration of relatively hydrophilic drugs (salicylate and acetazolamide) in the state of a drug-protein binding equilibrium. When an excess volume of a drug-albumin mixed solution was injected directly to this column, the drug was eluted as a broad peak with a plateau region following the protein peak. When the free drug fraction was higher, a larger injection volume was necessary to obtain the plateau region. The free drug concentration was determined from the plateau height; the results agreed well with those obtained by the ultrafiltration method. The total salicylate concentration could be simultaneously determined from the peak area. The present method was applied to an estimation of the salicylate-albumin binding parameters. The obtained values agreed well with the reported values. The present method enables a simple and rapid determination of free drugs in protein binding equilibrium.

Square Wave and Square Wave Adsorptive Stripping Voltammetric Comparison of the Anti-Inflammatory Drugs Piroxicam and Tenoxicam

Abstract: Two nonsteroid anti-inflammatory drugs, Piroxicam and Tenoxicam, are shown to be strongly adsorbed on mercury electrodes Using this phenomenon to accumulate these compounds at the static mercury-drop electrode prior to square-wave voltammetric measurement, sub-nanomole sensitivities are readily achieved A preconcentration potential of -06V vs Ag/AgCl/KCl(s) was used for both drugs The adsorptive stripping response was evaluated with respectto accumulation time and potential, analyte concentration, and electrolyte nature and concentration Ascorbic acid up to 1×10-4M has no effect on the Piroxicam peak, but results in enhanced response for the Tenoxicam adsorptive stripping peak Studies were performed at pH 40 and 20 for the two drugs; at these values two and four electrons are transferred, respectively The detection limit was 7×10-10M for Piroxicam and 1×10-10M for Tenoxicam, the latter being even more sensitive (5×10-11M) in the presence of ascorbic acid Applicability of square wave voltammetry to urine samples was demonstrated The detection limit is 5×10-8M and 5×10-9M (in presence of 1×10-5M ascorbic acid) for Piroxicam and Tenoxicam, respectively, in urine samples diluted ten-fold with the supporting electrolyte

Fabrication of a Fiber-Optic-Based Electrochemiluminescence Sensor and Its Application to the Determination of Oxalate

Abstract: The first reaction is oxidation of oxalate by the anodically generated Ru(III) complex. The Ru(II) complex is easily reduced with the generated CO 2• − to give the Ru(I) complex. Electron transfer from the Ru(I) to the Ru(II) gives an excited state of the Ru(II) which emits light

Determination of Hydrogen Peroxide with Fluorescein Chemiluminescence Catalyzed by Horseradish Peroxidase

Abstract: The determination of trace hydrogen peroxide (H202) is of considerable importance in both atmospheric and clinical analyses. In general, H202 is determined by spectrophotometric and fluorescent methods based on the coupling oxidation of dyes with H202 using horseradish peroxidase (HRP) as a catalyst.\"2 Recently, chemiluminescence (CL) methods by using luminol3 and peroxyoxalate4 reactions have been developed, thus lowering the detection limit of H202. Eosin, one of xanthene dyes, is also accepted to undergo a CL reaction with H202, as mediated by HRP.5,6 However, very little emphasis has been placed on the use of xanthene dyes for the determination of H202. In the present study we tested the CL reaction of H202 with eight xanthene dyes using HRP; the structure is presented in Fig. 1. As a result, fluorescein was found to be more sensitive than Eosin Y for the determination of H202. Based on this finding, we propose a novel method for the determination of H202 by using fluorescein.

Extraction behavior of silver ion with cyclic and acyclic tetrathio ethers and the molecular structures of the silver complexes.

Abstract: The liquid-liquid extraction of silver ion with two cyclic and four acyclic tetrathio ethers was examined. The extractability of an acyclic tetrathio ether was superior to that of the corresponding cyclic one. The mole ratio of extracted silver complexes was Ag:ligand:picrate=1:1:1, except in the case of 1,4,8,11-tetrathiacyclotetradecane (TTCT). X-Ray crystallographic analysis of the extracted Ag-TTCT-picrate complex was carried out. It becomes clear that the dimeric complex cation, [Ag 2 (ttct) 2 ] 2+ , was formed in the solid state. Each silver(I) ion has the coordination number 4 and binds with four sulfur atoms to form a distorted tetrahedral configuration. Thus, two silver(I) ions are sandwiched between two TTCT molecules. The structure of the complex cation is similar to that of previously reported silver-13,14-benzo-1,4,8,11-tetrathiacyclopentadec-13-ene picrate

Ion chromatographic determination of sodium, potassium, magnesium and calcium ions in river water

Abstract: The factors affecting the ion chromatographic separation of the alkaline earth metal cations on silica gel columns were investigated using different types of dicarboxylic acids as retention modifiers. The mobile phase pH and acid concentration showed marked influence on the separation of the analytes. When a 0.002 mol dm −3 lithium oxalate solution of pH 7 was used as a mobile phase, the major four cations in river water (Na + , K + , Mg 2+ and Ca 2+ ) were completely separated on a Nucleosil column (50mm×4.6mm i.d.) within about 16 min.

Gas Chromatography/Mass Spectrometric Determination of Traces of Hydrophilic and Volatile Organic Compounds in Water after Preconcentration with Activated Carbon

Abstract: The authors have developed an analytical method for extracting trace amounts of 15 hydrophilic compounds in water using gas chromatography/mass spectrometry coupled with an activated carbon preconcentration procedure. As internal standards, perdeuterated p-dioxane and N, N-dimethylformamide were added to 11 of a water sample; the water was passed through a granular activated carbon column. Organic substances adsorbed on the activated carbon were eluted with acetone and dichloromethane; the extract was then concentrated to 10ml with a Kuderna-Danish concentrator. Quantitative analyses using GC/MS with a selected ion monitor (GC/MS-SIM) were performed to measure the recovery efficiencies of the 15 compounds spiked into water samples at concentrations of 0.2 and 2.0μg/l. The recovery efficiencies through the internal standard method of the compounds, except alcohols and acetonitrile, gave more than 90% and their relative standard deviations were less than 7% at a concentration of 0.2μg/l. In this study, it was confirmed that the activated carbon preconcentration procedure is useful for extracting trace amounts of polar compounds which have a log P value (dichloromethane-water partition coefficient) greater than -0.5, except for compounds containing a hydroxy group or having a very small molecular weight. The method was applied to the analysis of river water and seawater for polar compounds. p-Dioxane, 1-propanol, N-nitrosodimethylamine, N-nitrosodiethylamine, N, N-dimethylformamide and N, N-dimethylacetamide were detected below the μg/l level.

Information Theory of Optimization in Chromatography

Abstract: A theory on flow rate optimization in column chromatography is presented on the basis of information theory. The quality of a given chromatogram is evaluated by the information flow v which is defined as the time-averaged amount of Shannon mutual information called FUMI. The theory developed here is a universal one: the new formula of FUMI, put-forward here, takes a general form applicable to system evaluation, design and optimization of any chromatographic variables which can be related to Gaussian peak shape.

Determination of isoniazid, acetylisoniazid and isonicotinic acid in human urine by high performance liquid chromatography coupled with postcolumn photochemical reaction and fluorescence detection.

Abstract: A high performance liquid chromatographic method involving postcolumn photochemical reaction and fluorometric detection has been developed for the determination of Isonicotinic acid, acetylisoniazid and Isoniazid in human urine. These compounds are separated by reversed phase chromatography using 0.07M phosphate buffer (pH 6.8) containing 100mM hydrogen peroxide as a mobile phase. The compounds in the column effluent are irradiated with ultravioletlight to give fluorescence. The fluorescence is monitored with excitation at 316nm and emission at 418nm. The calibration curves for Isonicotinic acid, acetylisoniazid and isoniazid are linear over the ranges of 0.1-120, 1.0-180 and 0.5-200ng, respectively. The mean recoveries of isonicotinic acid, acetylisoniazid and isoniazid from urine are more than 92%. This method can be applied for acetylator phenotyping.

Potentiometric determination of ethanol in alcoholic beverages using a flow-injection analysis system equipped with a gas diffusion unit with a microporous poly(tetrafluoroethylene) membrane.

Abstract: The selective determination of ethanol in alcoholic beverages is performed by a flow-injection analysis method using gas-diffusion separation. The determination is based on the oxidation of alcohol permeating across a porous membrane with dichromate and the reduction of excess dichromate with ferrous ion in a flow system. The concentration of ferric ion formed is potentiometrically measured with an oxidation-reduction potential electrode and is indirectly related to the alcohol content of the sample. Analytical results using the proposed method are in agreement with those obtained by a specific-gravity method (current official method in Japan) as well as by a gas-chromatographic determination

Ligand Effect on Redox Reaction of Metal Ions and Its Application to Potentiometric Titration of Chromium(VI) and Copper(II) with Iron(II)

Abstract: The effect of complexing agents on the titration of chromium(VI) and copper(II) with iron(II) was studied. In general, iron(III) forms more stable omplexes than iron(II), so that the potential of the system Fe(III)/Fe(II) is lower in the presence of a complexing agent than in its absence. Thus the addition of a complexing agent increases the sharpness of the end point of titration with Iron(II). The presence of pyrophosphate improves the potential break at the equivalence point of chromium(VI) with Iron(II). The use of neocuproine together with pyrophosphate is very effective in the titration of copper(II) with Iron(II).

Determination of vitamin D3 and 25-hydroxyvitamin D3 in sera by column-switching high performance liquid chromatography with fluorescence detection.

Abstract: A column-switching high performance liquid chromatographic method with fluorescence detection for the determination of vitamin D3 and 25-hydroxyvitamin D3 in human and rat sera is described. The vitamins in a lipid extract from serum, obtained by solid-phase extraction technique using a Bond-Slut C18 cartridge, are converted with 3, 4-dihydro-6, 7-dimethoxy-4-methyl-3-oxoquinoxaline-2-carbonyl azide into the corresponding fluorescent derivatives. The derivatives are separated from endogenous interfering substances by column-switching chromatography. The chromatographic system consisted of a precolumn chromatography for clean-up of the derivatives and an analytical column chromatography for the complete separation of the derivatives. The derivatives are detected fluorometrically at excitation and emission wavelengths of 360 and 440nm, respectively. The detection limits (S/N=3) for vitamin D3 and 25-hydroxyvitamin D3 are 15 and 8fmol, respectively, in a 10μl injection volume. The sensitivity permits simultaneous determination of the vitamins in 1ml of normal human and rat sera.

Solvent extraction of lanthanoids(III) with N-alkylcarbonyl-substituted N-phenylhydroxylamines.

Abstract: Several N-alkylcarbonyl-substituted N-phenylhydroxylamines (R-PHAs) were synthesized for use in lanthanoids(III) extraction. They were N-octanoyl-, N-(3, 5, 5-trimethylhexanoyl)-, N-(4-butylcyclohexanoyl)-, N-(4-butylbenzoyl)-, N- (2-propylpentanoyl)-, and N-(2-hexyldecanoyl)-N-phenylhydroxylamines. The distribution ratio of a lanthanoid(III) ion between the carbon tetrachloride and aqueous phases was examined as functions of the pH and R-PHA concentration at 298K and the ionic strength, 0.1 (NaNO3). Sodium tartrate (1×10-2mol dm-3) was present in the aqueous phase. Lanthanoids(III) were extracted as a self-adducted chelate, ML3(HL)2, with all the R-PHAs used. The conditional extraction constants and the separation factors of lanthanoids(III) with R-PHAs were evaluated. Among the R-PHAs, N-(2-hexyldecanoyl)-N-phenylhydroxylamine was most promising for the separation of heavy lanthanoids(III). Appropriate branching at the α-position of the carbonyl group seemed to transmit the R-PHAs different chemical properties with respect to the straight chain R-PHAs.

Determination of trace metals in biological samples by inductively coupled plasma atomic emission spectrometry with discrete nebulization after microwave decomposition.

Abstract: Trace metals in some biological samples were measured by the discrete nebulization technique in inductively coupled plasma atomic emission spectrometry. The small spray chamber and the time-sharing background correction system were used for the rapid measurements. Small amounts of the samples were decomposed quickly in a sealed PTFE vessel in a microwave oven. The analytical results for Al, Cu, Fe, Mn and Zn agreed well with the certified values and also with those obtained by continuous nebulization.

Synchrotron X-Ray Rietveld Analysis of α-Hafnium Phosphate

Abstract: The crystal structure of α-hafnium bis(monohydrogen orthophosphate)monohydrate, an inorganic ion-exchanger, was solved by the X-ray Rietveld technique utilizing synchrotron radiation (SR) as the X-ray source This compound is monoclinic with space group P21/n and cell parameters a=90142(1), b=525665(5), c=154768(2)A ??_ and β=101636(1)° Intensity data were collected by a capillary method with monochromatic X-rays of wavelength λ=149977(1)A The results were compared with those obtained by a conventional X-ray source and the advantages of SR in Rietveld analysis were verified Despite the difference in the Li-ion exchange behavior between the α-hafnium phosphate and the α-zirconium phosphate, both phases were found to be isostructural with each other

Formic Acid-Ammonium Formate Buffer System for Thermospray Liquid Chromatography/Mass Spectrometry

Abstract: A buffer system consisting of formic acid and ammonium formate was investigated as a strongly acidic mobile phase for thermospray liquid chromatography/mass spectrometry (TSP LC/MS). The behavior of the buffer was examined with regard to the relation between vaporizer control temperature and vaporizer tip temperature. Total intensity of solvent ions and sensitivity for target compounds as a function of vaporizer control temperature were also presented. The behavior of the formic acid-ammonium formate buffer was similar to that of an ammonium acetate aqueous solution, the usual mobile phase for TSP LC/MS. The applicability of the new buffer system to the compounds which required an acidic mobile phase was investigated. The new buffer system was found to reduce the peak tailing of amines and retain acids better than an ammonium acetate solution or an acetic acid-ammonium acetate buffer system.

Fluorometric Determination of Boric Acid by High Performance Liquid Chromatography after Derivatization with Chromotropic Acid

Abstract: L'acide borique reagit avec l'acide chromotropique pour former un complexe anionique, detecte par fluorimetrie, apres separation par HPLC. La formation du compose acide borique/acide chromotropique est favorisee par la presence de sels d'ammonium quaternaire. Les teneurs en bore dosees sont inferieures au ppb

Effects of Alkali and Alkaline Earth Metal Chlorides on the Atomization of Lead and Chromium in Graphite Furnace Atomic Absorption Spectrometry

Abstract: Potassium chloride, calcium chloride, sodium chloride and magnesium chloride cause many different types of interference in the determination of lead and chromium by graphite furnace atomic absorption spectrometry. Simultaneous volatilization of the analyte and the interferent from different, but close, points in the tube are very helpful in the explanation of interference mechanisms. The kind of interference that affects the sensitivity of the determination depends on the thermal behavior of the matrix before and during atomization of the elements. If chloride vapor is formed by decomposition of the matrix before or during atomization of the analyte elements, the formation of a metal chloride in the gas phase may be responsible for decreasing in the sensitivity. If, on the other hand, the matrix is present as a solid or liquid while the elements atomize, the occlusion of the analyte in the bulk of the matrix and the loss by a carrier-type mechanism or a slower transfer of heat to the analyte delaying the atomization cause some changes in the sensitivity. Expulsion of analyte vapors by expanding matrix gases was not effective due to the low heating-rate of the system used

Determination of the Sulfate Ion Concentration in Rain Water by Flow Injection Analysis Incorporated with a Barium Chloranilate Reaction Column

Abstract: The concentration of sulfate ions in rain water was determined by a flow-injection method using a reaction column packed with barium chloranilate powder. Aqueous ammonium chloride (0.5%) containing 50% ethanol was usede as a carrier at a flow rate of 1.9 ml/min. The chloranilate ion concentration, which corresponds to the sulfate ion concentration, in the carrier from the reaction column was monitored by a photometric detector at 530 nm. Interferences by multivalent cations were eliminated with use of a cation-exchange column inserted in the upper stream of the reaction column. The concentrations of sulfate ions in rain water (4-100ppm) were quickly determined (one sample per minute) with high reproducibility. The results agreed well with those obtained by the standard manual method