The variation of the standard deviation of the molecular weights determined by electrospray with the average charge number of multiply charged ions is investigated for peptides and proteins with molecular weights ranging from 1000 to 20000. This result shows the tendency that the standard deviation of experimentally determined molecular weights increases with the average charge number of multiply charged ions. It is found that the molecular weight determination by electrospray accompanies the error of at least the product of 0.06 and the average charge number in the experiment.

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Passage of radio frequency current through a large diameter ferromagnetic wire gives rise to surface heating. This happens because of maximum skin effect resistance and eddy current loss at the surface of such wire. This phenomenon was successfully exploited for desorption of five thermolabile as well as many volatile compounds. The desorbed molecules were subjected to EI and/or CI ionization in a double focussing mass spectrometer. Results show that this method of desorption compared favorably with others for mass spectral analysis.

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Carbon-13 NMR spectra of isomers of four mono- and three diisopropyldibenzofurans were recorded by an NMR spectrometer with a magnet of 9.4T (or 400MHz type). Even if the sample was a mixture of components or was of only 50% purity, unequivocal assignments were obtained by means of carbon-proton correlated spectroscopy (C-H COSY). Based on the α-effect by isopropyl group, and with the assistance of quaternary spectra (QUAT), one of diisopropyldibenzofurans was determined to be 2, 4-isomer, and not 1, 3-isomer which can not be ruled out by ¹H NMR. The chemical shifts of the isopropyl groups are more dependent on substituent positions in ¹³C than in ¹H NMR spectra. All 36 possible kinds of isopropyldibenzofurans are distinguishable using the present results together with ¹H NMR data.

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The sulfur-33 NMR spectra at natural abundance for sodium, cupric, cadmium and cesium sulfates besides sulfuric acid were recorded. Ferric and nickel sulfates did not give spectra because of their strong ferromagnetism. A very sharp peak at 33.5ppm downfield from ammonium sulfate was observed for sodium thiosulfate. Dimethylsulfate and ethane sulfate also showed spectra with a poor signal-to-noise ratio, with accumulations of 10⁵ transients at 19.19MHz.

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The potentiometric behavior of valinomycin incorporated bilayer lipid membranes (BLMs) was studied in view of a comparison with its solvent polymeric membrane counterpart. The preparation of membranes has greatly relied on the Takagi-Montal method as well as synthetic lipid chemistry. The prepared membrane was first characterized regarding its electrical resistance, electrical capacitance and the effect of gramicidin to reveal its Bilayer nature. The membrane potential was systematically studied in terms of i) the valinomycin concentration in the lipid membrane and ii) the effect of the lipid charge. The observed membrane potentials were compared with those of valinomycin-incorporated solvent polymeric membranes in terms of i) the detection limit, ii) the dynamic range and iii) the selectivity for alkali metal ions. It was found that the detection limit, dynamic range and optimum valinomycin concentration for the K⁺ ion-induced Nernstian response for the BLM electrode were comparable to those of the solvent polymeric membranes. The selectivity coefficients (K^pot_ij) for alkali metal ions determined by the separate solution method were also comparable to those of liquid membranes. However, a marked difference between both the membranes was found with respect to the effect of the membranous charge. The potentiometric response of the BLMs was found to depend on the charges of lipids. With negatively charged BLMs, the detection limit and dynamic range for K⁺ ions were improved. On the contrary, the response with positively charged BLMs was significantly reduced without any change in the Nernstian slope. This effect of lipid charge was compared with the anion effect for a solvent polymeric membrane. Finally, the first successful formation of planar BLMs using totally synthetic lipids was also demonstrated.

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A diode-laser-based indirect fluorometric detector that monitors a near infrared dye, IR 125, added to the mobile phase for reversed-phase high-performance liquid chromatography, was evaluated. Analytical measurements of n-alkyl alcohols were made by measuring the induced change in the IR 125 fluorescence signal at the alcohol retention times. Limits of detection were on the order of 10^-8mol injected. Several isocratic separations were carried out at different IR 125 concentrations in different acetonitrile : pH6 sodium phosphate aqueous buffer mobile phase ratios. The results indicate that a small dye/analyte transfer ratio is limiting the capabilities of the detector. However, the low noise and highly selective excitation characteristics of the diode laser present the potential for this detection scheme to attain a detection limit of 10^-11M at the detector for analytes with a transfer ratio of 1.

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Chemiluminescence (CL) observed in a reaction between OH radicals and nucleosides or their derivatives is applied to their sensitive determinations by a flow injection method. The OH radicals are produced by the reaction with hydrogen peroxide and cobalt(II)-1, 10-phenanthroline complex in alkaline solution. The proposed flow system is comprised of three flow lines for cobalt(II), 1, 10-phenanthroline and hydrogen peroxide. The proposed CL is specific to nucleosides and their related compounds. Their detection limits ranged from 68pmol (uridine-5′-diphosphoglucose; UDP-Glu) to 89 pmol (guanosine) in a 10μl injection volume. The relative standard deviation is 1.2% in 5 repeated runs for UDP-Glu of 178pmol in a 10μl injection volume. Analytical time required is ca. 2s.

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The suction-flow on-line column preconcentration of cadmium from an aqueous solution for inductively coupled plasma atomic emission spectrometry (ICP-AES) was investigated utilizing a column packed with gas chromatographic-grade porous active-carbon impregnated with 8-quinolinol. A sample solution (pH 2.5-7) and a buffer solution were sucked, mixed and pumped through the column; subsequently, the analyte was eluted directly into the nebulizer of the ICP with 1cm³ of 0.5mol dm^-3 hydrochloric acid. Using 5cm³ of the sample solution, this method gave a signal enhancement of 1 order of magnitude for cadmium, better than that obtained by a conventional nebulization system; the detection limit was 0.25ng cm^-3 with a sampling rate of 35h^-1. The relative standard deviation for 500ng cadmium was 1.1% (n=10). This column could be used for more than 80 replicate analyses when 5cm³ of a standard solution containing 100ng cm^-3 cadmium(II) was introduced into the system each time. The proposed method was applied to the determination of cadmium in certified biological reference materials.

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Lead, tin, indium or selenium forms an alloy of a palladium matrix modifier during its atomization process in a graphite furnace. This process was studied by measuring the effective (atomic) vapor temperature, showing that the atomization occurred in specific phases of the alloy. It was found that Pb is atomized in the phases Pd₃Pb₂-Pd₃Pb, Sn in the phases Pd₃Sn₂-Pd₂Sn-Pd₃Sn, In in the phases PdIn₃-Pd₂In₃-PdIn-Pd₂In, and Se in the phases Pd_mSn_n-Pd. In a Pb-Fe system having no solid solution at any concentration range, the temperature-rising curve was almost the same as the curve for Pb in the absence of other co-existing elements. Fe, as the co-existing element, did not influence the atomization of Pb. For an Ni-Pd alloy, having different characteristics to that of the above-mentioned alloys, the temperature of the sample rose, reached the melting point of Ni (of Pd), formed a molten alloy and then followed flash atomization, as if an explosion had occurred. This was because the melting point of the alloy was lower than the 100% Ni (or Pd) metal.

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Trace amounts of ytterbium in seawater were coprecipitated with iron(III) hydroxide, and the precipitate was dissolved in 2ml of 8mol/dm³ hydrochloric acid. Iron(III) ions were removed by extraction with 2, 6-dimethyl-4-heptanone, and a 20-μl aliquot of the aqueous phase was directly injected into a graphite furnace atomizer. Ytterbium in seawater was found to be (0.62-1.35)×10^-9g/l.

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The effect of the addition of Cr(NO₃)₃ on graphite-furnace atomic absorption spectrometry for lead in the presence of MgCl₂ was investigated from the viewpoint of its mechanism. X-Ray photoelectron spectrometry for the charring product of a mixture of MgCl₂, Cr(NO₃)₃ and lead indicated the presence of Pb(II), Cr(III) and Cr(VI). An analysis of the charring product of a mixture of MgCl₂ and Cr(NO₃)₃ by ion chromatography indicated a remarkable loss of chloride ions at a lower charring temperature (620K), before the fusion of lead chloride occurred. It was suggested that the loss of chloride ions resulted from the for mation of gaseous species, produced by redox reaction. Atomic absorption measurements of lead and its kinetic analysis were carried out in Mg(NO₃)₂, MgCl₂, MgCl₂ with Cr(NO₃)₃, Cr(NO₃)₃, CrCl₃, (NH₄)₂CrO₄ and K₂Cr₂O₇. A comparison of the appearance temperatures of the lead signal and the Arrhenius activation energies of lead atomization among each matrix showed that Cr(III), e.g. Cr₂O₃, dominantly affected the atomization of lead.

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A method is described for the determination of trace amounts of anthraquinonesulfonates (ASs) in environmental samples such as river water and soils. ASs in aqueous samples were adsorbed on Dowex WGR weakly anion exchange resin and eluted with 1.5M hydrochloric acid. The eluates were converted into volatile chloroanthraquinones by chlorine substitution using sodium chlorate in hydrochloric acid solution and determined by gas chromatography-selected ion monitoring (GC-SIM). Soil samples were treated similarly to aqueous samples after sonication with distilled water at 80°C. The detection limits for sodium anthraquinone-1-sulfonate (1-AS) and sodium anthraquinone-2-sulfonate (2-AS) were 0.005ng and 0.02ng, respectively, with 1μl of injected sample. The recoveries of 1-AS and 2-AS from river water and soil samples were over 86% and 62% with relative standard deviation (RSD) below 7% (n=7). This method is capable of simultaneous determination of ASs with sufficient sensitivity and selectivity to be applicable to environmental samples.

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The monitoring of the asbestos concentration in piled particulate matter on roads generated from the brake friction materials of automobiles has been studied. The concentration of dust produced by brake friction materials in automobiles was determined based on the concentration of phenolic resin in piled particulate matter; further, the concentration of asbestos was estimated from the concentration of the brake friction materials. Piled particulate matter on roads in Tokyo area was analyzed, and the concentration of asbestos released from brake friction materials during traffic was estimated. The asbestos concentrations in the dust of brake friction materials were 0.36-2.1, 0.20-3.0 and 1.5-3.1mg/g on national highway No. 246 and loop lines No. 7 and No. 8, respectively. The concentration of asbestos dust having a long-fiber shape was estimated to be several tens ppm or less.

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Novel compounds having two hydroxyoxime moieties were prepared and used for copper extraction from an acidic sulfate solution. Logarithmic plots of the copper distribution ratio vs. pH and the extractant concentration showed that the copper extractions were established through the formation of 1:2 (Cu²⁺: extractant) complexes. At concentrations below 1mM, however, the existence of the m:m (m>1) complexes were suggested by UV (molar ratio method) and ESR measurements. The half-extraction pHs of the extractants were in the range of 1.8 to 2.0 and were lower than that of LIX65N.

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A highly sensitive, rapid and facile method is described for the determination of copper(II). A small amount of copper(II) is quantitatively collected on a membrane filter made of cellulose nitrate as a colored complex with N, N-diethyldithiocarbamate without carrier substances. The complex, together with the membrane filter, is dissolved in N, N-dimethylformamide (DMF), and the absorbance of the solution is measured for the determination. The calibration curve was linear from 0.1 to 8.8μg of copper(II) in 3.0-cm³ DMF. The apparent molar absorptivity of copper(II) was 1.20×10⁴ dm³ mol^-1 cm^-1. The relative standard deviations at 1.2 and 6.0μg of copper(II) were 4.3% (n=13) and 1.1% (n=12), respectively. The method was applied to the determination of copper in environmental certified reference material (NIES No. 1, Pepperbush) and water samples.

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The extraction of cyanate, thiocyanate or selenocyanate ions with the copper(II) complex of di-2-pyridylmethanone 2-Quinolylhydrazone (DPQH) into benzene has been investigated spectrophotometrically at 25°C and μ=0.1. Copper(II) reacts with DPQH in a weakly acidic solution to form a dipositively charged mono complex (Cu(HL)²⁺) with the formation constant of logβ_Cu(HL)=9.47. This complex undergoes deprotonation to a highly colored CuL⁺ species in the higher pH range, the proton dissociation constant having been determined to be pK_ac=4.53. In the presence of the abovementioned anions both complex species can be extracted into benzene as a highly colored ternary complex, Cu(L)A (A=NCO^-, NCS^- or NCSe^-). The extraction constant, defined as K_ex=[Cu(L)A]_o/[Cu(L)⁺][A^-] (the subscript (o) denotes the organic phase), is found to be 4.96 for NCO^-, 6.15 for NCS^- and 5.56 for NCSe^- in logarithmic units. On the basis of the above observations, a sensitive spectrophotometric method for the determination of up to 3×10^-5M of the anions has been developed by measuring the absorbance of the organic phase at 540nm.

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Reaction conditions in rare earths(RE)-Xylenol Orange(XO)-cationic surfactant ternary system were studied in detail. Conditional molar absorptivities up to 150000mmol^-1 cm² were reached. Highly sensitive spectrophotometric method for 15 RE elements (REE) was evaluated under optimal conditions of 0.06mmol dm^-3 XO, 0.6mmol dm^-3 cetylpyridinium bromide, and 0.01mol dm^-3 acetate buffer of pH 4.50. Calibration plots measured at 600, 610, and 620nm were linear up to 5.5μmol dm^-3 REE. The best detection limits of 0.04-0.20 μmol dm^-3 REE were reached at 610nm. In comparison with the previous results, the sensitivity of determination was increased and the range of knowledge of the mentioned ternary system was extended.

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An uranyl ion (UO₂²⁺) reacts with 2-(p-methylphenylazo)pyridine in thiocyanate system. The species is extractable quantitatively into methyl isobutyl ketone (MIBK) in the presence of nitrate ion, showing an absorption maximum at 370nm. Beer′s law is obeyed over the range 0.15-1.5μg of uranium/ml. The molar absorptivity and Sandell′s sensitivity are 0.166×10⁴ l mol^-1 cm^-1 (on the basis of uranium content) and 0.0014μg/cm², respectively. Various international geochemical reference samples were chosen to check the validity of the method. The results obtained were in good agreement with the published data.

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The acid-base equilibrium constant of the active component of the commercial extractant LIX 54, 1-phenyl-1, 3-decanedione, has been determined in a water/alcohol mixed solvent (25% ethanol) at 298K using 1.0mol dm^-3 KCl as an ionic medium. Graphical and numerical treatment of spectrophotometric data have led to the value pK_a=9.73±0.05. The distribution, aggregation and interactions of the reagent with other extractants used in synergistic mixtures are also discussed. A comparison of the extraction of Cu(II), Ni(II) and Zn(II) from nitrate solutions by the reagent and by mixtures of the reagent with additional ligands in toluene has been made.

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Eleven known samples of mixed powder of cocaine and sodium hydrogencarbonate were measured by an X-ray diffractometer; the I/I₀ values at 18 or 19 2θ-values were used for data base. Multivariate analyses (such as cluster analysis, cluster analysis from deviation and principal component analysis) were carried out by the use of a 12×18 or 12×19 matrix, and the approximate cocaine contents in unknown samples were determined. The accurate cocaine contents were calculated from the principal component score. The calculated values of the cocaine content agreed well with the theoretical values.

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