A new spectroscopy for solution, designated Photoelectron Emission Spectroscopy, has been developed. Since this technique is applicable to almost any solution and provides the ionization potential of solutes, the ionization potentials can be measured for solutes which give neither a reproducible oxidation potential by electrochemistry nor the ionization potential in a vacuum by photoelectron spectroscopy. Since photoionization is a one-electron oxidation reaction, the ionization potential in solution is very similar to the oxidation potential in character. Therefore, the ionization potential measured by the present method is designated as the optical oxidation potential. In this review the optical oxidation potential values are given for organic molecules, metal complexes and halide anions, and are compared with the electrochemical oxidation potentials and the results by other spectroscopies. In order to make proceed an oxidation reaction at an electrode, there is a limit for the electrode potential, i.e. no higher potential is necessary to accelerate the reaction, which is the optical oxidation potential proposed here, while there exists a lower limit known as the standard oxidation potential. The difference between these two oxidation potentials provides a kinetically important parameter, the reorganization energy for electron-transfer reaction. The present spectroscopic method has proved to be a technique which can provide a new measure of the reducing power of solvated species and new insights into the solvation energy and solvation structure. Its application to the analysis of an air/solution interface is also described.

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This is a review article concernning the development of a gas chromatographic analytical method for the analysis of 70 air toxic compounds. Not only the operating conditions, but also the column system is optimized. Optimization of the GC analytical methods for air toxic compounds is based on a unified method with a system comparising two columns. An optimization strategy with stepwise temperature programming has been used to achieve optimum separations. Two sets of usual GC instruments with specially developed software, Chromatogram Analyzer, have also been used for this purpose. Some essential retention data and typical results are presented in this paper.

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High-performance liquid chromatographic determination of guanine and its nucleosides and nucleotides in rat brain tissue and human erythrocytes has been accomplished by means of a precolumn fluorescence derivatization method. These compounds in deproteinized samples were selectively converted with phenylglyoxal to fluorescent derivatives. The derivatives in the reaction mixture were separated by both reversed-phase chromatography using a TSKgel ODS-120T column and ion-pair reversed-phase chromatography using an Asahipak ODP-50 column. GTP, GDP, GMP and guanosine in the biospecimens were quantified. The detection limits (S/N=3) for the compounds were 0.11-2.54pmol.

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A fluorometric method based on the measurement of two nucleobase pairs of guanine-cytosine and adenine-thymine was developed for the accurate quantification of double-stranded DNA. Two fluorescence reactions with phenylglyoxal and chloroacetaldehyde are utilized for detection of the guanine and adenine moieties in DNA, respectively. The optimized conditions of the respective reactions permit quantitative determination of DNA at concentrations as low as 0.15μg ml^-1. The DNA-content values determined for five commercial DNA preparations were 80-103% of their actual weights.

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For quantification of histamine, we developed a highly specific and sensitive method of postcolumn fluorescence detection HPLC using a tetrahydrofuran solution of orthophthalaldehyde. Its detection limit was 2-5pg. This method was applied to the measurement of histamine in human blood and urine samples. Analysis by LC/MS and NMR suggested that the fluorophore in this method has an isoindole structure.

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FeCl₂ was found to be a useful catalyst for the determination of H₂O₂ based on the chemiluminescence of a Cypridina luciferin analogue, 2-methyl-6-phenyl-(p-methoxyphenyl)-3, 7-dihydroimidazo[1, 2-a]pyrazin-3-one (MCLA). By this method, H₂O₂ was detected in a range from 300pmol/ml to 10nmol/ml. In addition, glucose oxidase (GOD) was determined in a range from 1.18×10^-5units/ml (280amol/ml) to 7.56×10^-4units/ml (17.9fmol/ml) when GOD was incubated with glucose for 10min at 34°C.

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A new method which allows a rapid hydrothermal decomposition of polyamides and simultaneous derivatizations, followed by an on-lined Curie-point heating-gas chromatography/mass spectrometry analysis is reported. The reactions were carried out in a sealed glass capillary with an acidic medium of hydrochloric acid (35%wt)/methanol/acetic anhydride 2.5:40:60, wt) at near-critical pressure and temperature (235°C). About 0.1mg of polyamides, including diamine-dicarboxylic acid and ω-aminoalkanoic acid-types, were decomposed in this acidic medium to diamines, dicarboxylic acids and ω-aminoalkanoic acids; the simultaneous methylation of the acids and acetylation of the amines was performed within 5min in a single step. The characteristic peaks of dimethyl dicarboxylates, methyl dicarboxylates and diacetyl diamines shown in their chromatograms definitely corresponded to the molecular compositions of the polyamides. The influence of the reaction reagent on the chromatograms and the quantitative reproducibility are also described.

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A method is described for the determination of trace amounts of indium in high-purity aluminum. Indium in an aluminum solution is extracted into xylene as its diethyldithiocarbamate complex and subsequently back-extracted into 100μl of nitric acid for the determination by graphite-furnace atomic absorption spectrometry (GFAAS). The extraction and back-extraction allow indium to be concentrated by about 2-10-fold from 0.2-1g of aluminum. The resulting solution is suitable for the determination of indium by GFAAS. The detection limit for indium was found to be 0.36ng g^-1 when 0.2g of an aluminum sample was used. The contents of indium in two real high-purity aluminum samples were found to be 0.88 and 10.9ng g^-1.

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A mixture of cobalt and aluminum nitrates proved to be useful as a matrix modifier for determination of germanium by graphite-furnace atomic absorption spectrometry. These metal nitrates acted as a thermal stabilizer for germanium in the furnace before atomization, and atomic absorption sensitivity for the analyte was improved by a factor of about 40 over that in the absence of metal nitrate. For the removal of chloride interference in the determination of germanium, a mixture of ammonium acetate with these metal nitrates was suitable as an additive, because chloride formation of aluminum was masked by acetate and the volatile ammonium chloride formed could be easily removed from the furnace. The tolerable concentration of coexisting chlorides was about 10 or more times greater than that in the absence of ammonium acetate. The sulfate interference could also be removed by the addition of a mixture of ascorbic acid and ammonium-EDTA with cobalt and aluminum nitrates. EDTA acted as a masking agent and the formed ammonium sulfate could be easily removed from the furnace. The tolerable concentration of coexisting sulfates was also about 200 times greater than that in the absence of these organic reagents.

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We developed a flow injection analysis method for the determination of trace aluminum in water coupled with on-line preconcentration on salicylideneamino-2-thiophenol immobilized glass beads (SAB) and spectrophotometric detection using Pyrocatechol Violet (PV). The FIA system consisted of two pumps, a 6-port switching valve, a concentrator column, a UV/VIS spectrophotometric detector and a recorder. A sample solution was combined with a succinic acid/ NaOH buffer (pH 6.0) and hydroxylammonium chloride and this mixture was loaded on the concentrator column. Aluminum retained on the concentrator column was eluted with 0.1mol dm^-3 nitric acid and mixed with PV. A colored PV-aluminum complex was spectrophotometrically monitored at 576nm. A linear relationship was observed between the peak height and aluminum concentration at a constant sample volume. A correlation coefficient of 0.9997 and determination limit of 3.7nmol dm^-3 were obtained for a sample volume of 10ml. Relative standard deviations were below 2% at nmol levels. Aluminum traces in some Kanazawa City tap water samples were determined by this method.

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An analytical method for the determination of iodate and iodide ions at theμg l^-1 level in mixtures was investigated. Iodide in samples was first oxidized with sodium nitrite; the free iodine liberated was then released from the solution by heating. Excess nitrite was destroyed with amidosulfuric acid (sulfamic acid). The iodate remaining in the solution was determined by a kinetic-photometric method based on the catalytic effect of iodine on the oxidation of chlorpromazine by hydrogen peroxide in a sulfuric acid solution. The total iodine was also determined by a similar analytical procedure without carrying out operations for the removal of iodide; the iodide was found from the difference between the two results. Mixtures of iodate and iodide in the 0.2-5μg l^-1 range of total iodine could be determined within an error of 10%. The proposed method has been successfully applied to a differential determination of iodate and iodide in natural fresh-water samples.

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Aqueous micellar solutions of alkylglucosides were separated into two phases at 0°C upon addition of polyethylene glycol 6000 (PEG) or Dextran T-500 (Dextran). One was an aqueous phase in which hydrophilic proteins, cytochrome c and peroxidase (horseradish), were retained, and the other was a surfactant-rich phase into which hydrophobic membrane proteins, bacteriorhodopsin and cytochrome b₅, were extracted. A combination of octyl-β-D-thioglucoside (OTG) (or nonyl-β-D-glucoside (NG)) with PEG (or Dextran) was the best choice for extraction of hydrophobic proteins. Extraction yields (50-90%) and concentration factors (7-30) of the hydrophobic proteins were dependent on the types of nonionic surfactants and water-soluble polymers. Solubilization and phase separation in processing cell membranes could be made in a single step at 0°C. Hence the present method would be useful for the purification of thermolabile proteins.

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A quasi-elastic laser scattering (QELS) method was applied to monitoring the capillary wave frequencies at a water/ nitrobenzene interface. A digital spectrum analyzer was adopted to improve the time resolution of the QELS method. As a result, each power spectrum could be obtained in 1s and saved in an additional 1s. The equipment was checked by monitoring capillary wave frequencies at a water/nitrobenzene interface covered with a monolayer of dipalmitoylphosphatidylcholine (DPPC), i.e. changes of interfacial tension caused by the formation of the monolayer at the interface were detected. The equipment was then applied to a chemical oscillation system. It was found that the interface of the chemical oscillation system was covered with a high density membrane during the chemical oscillation.

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Hydration of tributyl phosphate (TBP) at concentrations up to 0.3mol dm^-3 in dodecane (8.1 vol% TBP) was examined at 298K. Water extraction into TBP-dodecane solutions was measured and the data were analyzed as a function of TBP concentration in the organic phase and of water activity in the aqueous phase. The data analyses showed the presence of two TBP-water complexes in the organic phase. When the TBP concentration in the organic phase is low enough, only a TBP hydrate of TBP•H₂O is formed. However, at high TBP concentrations, this hydrate dimerizes to form (TBP)₂(H₂O)₂. The TBP-water stoichiometry taking account of these two complexes well explained the experimental data in the TBP concentration range examined.

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3, 5-Dinitro (3, 5-DNBPHA) and 2, 4-dinitro derivatives (2, 4-DNBPHA) of N-benzoyl-N-phenylhydroxylamine (BPHA) were synthesized. Their acid dissociation constants and distribution constants between chloroform and 0.1mol dm-3 potassium chloride solution were determined by a spectrophotometric method and a liquid-liquid distribution method, respectively. The solvent extraction of lanthanoids (Ln) with 3, 5-DNBPHA in chloroform was studied. The selected lanthanoids (Yb, Ho, Eu, Pr and La) were all found to extract with compounds as self-adducts of the form LnL₃(HL)₂, where L and HL denote the ligand anion and neutral ligand, respectively. The extraction constant and separation factor were compared with those of the methoxy derivatives of BPHA previously reported. It has become apparent that the lower is the pK_a value of the extractant, the larger is the extraction constant; further, the separation of lanthanoids becomes poorer as pK_a decreases.

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The selective effect of triethylenetetramine (Trien) on the retention behavior of sulfate in ion chromatography was studied. When Trien was added to an eluant as a counter ion, retention of sulfate was selectively shortened, while retention times of monovalent anions did not change. The cause for this phenomenon was the complexation of sulfate and Trien in an eluant. The stability constants of divalent sulfate-trivalent Trien and -tetravalent Trien complexes were estimated to be 936 and 4213 (40°C), respectively. As a practical application of this phenomenon, weakly retained monovalent species can be very well separated from both water dip and other species without prolonging the interval of injections.

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The system for analyzing C₂-C₆ nonmethane hydrocarbons (NMHC′s) using the gas chromatographic technique with an Al₂O₃/KCl PLOT column combined with a canister sampling device was successfully used to measure background air samples. The NMHC compounds stored in a humidified canister were stable. Any contaminated canister was easily cleaned under high-vacuum condition. A total of 52 compounds of C₂-C₆ NMHC′s were found; 34 of these were identified, and were consistent with results from laboratories around the world. One should be careful concerning eluent peak identification of the isobutane-acetylene and propyne-1-pentane pairs. An absolute quantification of 1-butane was checked within an 8% deviation by participating in an international hydrocarbon experiment. The detection limits were typically in the 10 part-per-trillion (v/v) range. The reproducibility was 5-7% precision at the 1-10ppb level. The system described here is capable of urban, remote and background air studies. Samples were collected at a remote ocean island of Lanyu, Taiwan, during the period from Sep. 20 to Oct. 18, 1992.

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Zone circulating flow-injection analysis (ZCFIA) is a multidetection method for a sample zone injected into a closed-flow system formed by connecting the inlet to the outlet of a single-line FIA manifold. Using a multi-step peristaltic pump, a set of damped curves were obtained under various revolution speeds of the pump. By analyzing these curves, a great deal of information concerning FIA theory was acquired. Correlations among the residence time, flow rate, length and inner diameter of the reaction coils, sample volume and dispersion coefficient were clarified. Several qualitative formulations were established and six qualitative results suitable for the various conditions involved were obtained. As result, several shortcomings and errors in the current FIA theory were determined.

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