Flow-injection analysis (FIA) is a rapid and precise technique of wide application. Although a number of automated flow-injection systems are commercially available, their applications to on-line analyses have scarcely been reported. In this study, FIA systems have been developed for the spectrophotometric determination of impurities (cobalt, copper and cadmium) in hydrometallurgical zinc refining. We have investigated the following flow-injection techniques: a method utilizing a non-dispersion sample zone in which a large sample volume is injected to deal with high-salt concentration solutions, a correction method for the system variation, and a computer-controlled variable-volume injector to expand the dynamic ranges of the proposed flow-injection system. We have also described the adsorption behavior of a number of elements on the anion-exchange resin (AG1-X8) in potassium iodide media. The anion-exchange methods have been brought into on-line flow-injection systems for the determination of trace impurities (potassium iodide medium for cadmium and bismuth, hydrochloric acid medium for nickel, cobalt, copper, thorium and uranium) in high-purity zinc metal with ICP-MS to minimize contamination and to handle a large number of samples in a short time. The advantages of applying automated FIA to process monitorings and on-line matrix separation in trace analyses are discussed.

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Many organic compounds of biological importance possess two or more polar function groups in close proximity. In chromatographic analysis, a suitable derivatization of the bifunctional groups has sometimes been used to enhance the sensitivity and selectivity for detection. Transforming 1, 2-diol compounds to the corresponding cyclic boronate derivatives has been more extensively used as a suitable derivatization method for gas chromatography and gas chromatography-mass spectrometry. Although applications to liquid chromatography have been comparably limited due to the susceptibility of the cyclic boronates to solvolysis, we have been demonstrated some instances in which such derivatives show considerable stability. In this paper we describe the utility of the boronate ester function as a derivative group for the characterization of 1, 2-diol compounds by reversed-phase liquid chromatography, and briefly survey the reactivity of boronic acid derivatives with a variety of 1, 2-diols. The present review covers the following : 1. synthesis of novel boronic acid derivatives and the development of highly selective and sensitive detection methods for diol compounds, 2. chromatographic optical resolution of enantiomeric diol compounds by optically active boronic acid derivatives, 3. molecular orbital methodological approach to prove the relationship between the stability and the molecular structures of boronates, 4. highly selective solid extraction for the chromatographic determination of diol compounds using phenylboronic acid-bonded gel. Several boronic acids, including naphthaleneboronic acid, phenanthreneboronic acid, 1-cyanoisoindole-2m-phenyl-boronic acid, dansylaminophenylboronic acid and ferroceneboronic acid have been successfully applied to the boronate formation of diol compounds chromatography. It has been confirmed that some diol boronate derivatives are remarkably stable, even under acidic aqueous conditions. A satisfactory gas chromatographic separation of the diastereomeric 2-(N, N-dimethylaminomethyl)ferroceneboronates derived from enantiomeric diols could be performed in the achiral stationary phase. In order to prove the relationship between the stability and the molecular structures of boronates, optimized structures of the boronates were calculated by the molecular orbital methodological approach. It has been confirmed that the C-C bond distances of the "stable" boronates are longer than those of the "unstable" boronates. The steroids, brassinolide and castasterone, were retained as their cyclic boronates formed on immobilized phenylboronic acid gel in a mixed solvent of pyridine and acetonitrile. After removal of impurities in the sample, parent steroids could easily be released from their boronates by a mixed solution of hydrogen peroxide and acetonitrile. The present method is the first time phenylboronic acid-gel has been used in the purification method of brassinosteroids in plants. The liquid chromatographic analytical method for cyclic boronates may contribute to identification studies on diol components with conformational rigidity or stereochemical hindrance in biological and pharmaceutical samples, and also to their screening in unknown compounds

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The depth profiling of dopants at the surface and interface of semiconductor devices requires high accuracy and high depth resolution. We have developed sputtered neutral mass spectrometry (SNMS) with laser post-ionization. The As depth profile through a thermally oxidized silicon/single crystal silicon interface was analyzed to demonstrate the accuracy of SNMS compared with secondary ion mass spectrometry (SIMS). The As secondary ion yield was much higher in oxidized silicon than in silicon. However, the SNMS profile was close to a Gaussian curve as expected. The SNMS profile near a silicon surface and the SNMS profile through a poly-silicon/silicon interface were also close to the expected curves; however the SIMS profiles were affected by surface or interface oxygen. Thus, SNMS measurement was shown to be free from matrix effects and to be capable of providing accurate depth profiles with under 10-nm depth resolution.

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Electrical potential oscillation across the liquid membrane of a water/1-octanol/water (including surfactant) system in the presence of drugs and drug ion transfer at the polarized nitrobenzene/water interface were studied. An apparatus for measuring the potential oscillation across the liquid membrane of a water/octanol/water system was developed, producing potential oscillation measurements with high reproducibility. A detailed investigation of the potential oscillation mechanism revealed that potential oscillation is due to the repetitive formation and destruction of a surfactant layer adsorbed at the interface between the octanol phase and water phase at which no previous surfactant had been added. The potential oscillation characteristics such as amplitude, oscillatory and induction periods were found to reflect the interactions between a drug and the surfactant layer. The oscillation mode was correlated with the pharmacological activity of hypnotic and anesthetic drugs. In order to obtain the ion transfer voltammograms of drugs, equations approximating the half-wave potential of drugs were deduced by considering dissociation of the drug molecule. Half-wave potential values obtained from the voltammograms were found to correlate with the pharmacological activity of certain drugs such as hypnotics and local anesthetics. Measurements of potential oscillation and ion transfer voltammograms can be used to evaluate the hydrophobicity of drugs, and thus may provide novel methods for evaluating drug structure-activity relationships.

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The principle, instrumentation, and applications of a novel chemical measurement method based on reaction heat-induced optical beam deflection (OBD) have been discussed in detail. A theoretical equation that describes reaction heat-induced OBD for a very fast reaction (impulse reaction) is first derived by considering the thermal diffusion process. For a slow chemical reaction, its reaction heat-induced OBD signal is treated with the concept of convolution. The neutralization reaction is used as a model fast reaction for verification of the derived theoretical equation and investigation of the basic experimental conditions. It has been demonstrated that the magnitude of reaction heatinduced OBD is proportional to the amount of reactant, and the reaction rate can be deduced by analyzing the time decay curve of the reaction heat-induced OBD signal. Applications of the method to redox reaction and enzyme reaction systems have also been investigated. Furthermore, real time one dimensional imaging detection for reaction heat-induced OBD is also demonstrated. Further development and applications of the method are also discussed.

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A ceramic carbon column has been used for the simultaneous determination and separation of several inorganic anions (F^-, Cl^-, NO₂^-, Br^-, NO₃^-, SO₄^2-, HPO₄^2-and I^-) by ion chromatography. Peaks of I^-and HPO₄^2-tailed badly with long elution times, which is attributed to the strong adsorption of carbon. The problem was solved by coating the carbon column with an anion surface-active agent, dodecylbenzenesulfonic acid(DBS), as a pretreatment of the column. The coating is accomplished by passing 0.1 mM DBS through the column (4.6 mm i.d. × 100 mm, Bio Tech Research) at a flow rate of 1.0 ml/min for one hour. The optimal mobile phase is 4 mM Na₂CO₃-1 mM tetrabutylammonium hydroxide (TBA) in 7.5% acetonitrile. Operating conditions are as follows: flow rate, 1.0 ml/min; column temperature, 30°C ; scavenger, 12.5 mM H₂SO₄. The calibration curve for iodide ion was linear with high correlation coefficients of more than 0.9998 and the relative standard deviation(RSD) of peak areas was 0.57% from 10 repeated measurements. The method was applied to microdetermination of iodine in organic compounds by both the oxygen flask combustion method and the direct injection method. The analytical results were in good agreement, within ± 0.2 % of the theoretical value for each sample.

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Determination of fluorine, chlorine, bromine and sulfur in organic compounds by means of Schoniger technique coupled with Ion chromatography has been newly performed. By using standard organic compounds, we have succeeded in suppressing the background of nitrogen oxide and carbon dioxide. Especially the values of fluorine and chlorine have much improved in accuracy. A great number of samples having these atoms in the same molecules need to be analyzed simultaneously. We synthesized the standard organic compounds with both atoms in the molecules. The curve response of each standard sample is limited by the ratio of the atomic composition. To determine unknown samples or compounds that have large differences in composition, it is better to use the suitable linear calibration curves for the respective compositions. For that reason we made three different calibration curves using compounds having different ratios of atomic compositions. An automatic selecting program was devised to select the proper calibration curve from those three. The total performance gave highly accurate results and was highly efficient and practical for determinations of a large number of samples containing compounds with many elements.

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Atomic charge densities and atomic distances were obtained for organic polymers using the molecular orbital method (MO method). The binding energies of C_1S, O_1S, and N_1S were correlated with the calculated atomic charges and atomic distances. The following correlations were found for the binding energies (BE) of C_1S, BE(eV)= 286.03+7.81X_i, or BE (eV)=286.10+9.16X_i+ 1.02Σ (X_j/r_ij), where X_i is the atomic charge density of the marked atom, X_j that of the adjacent j-th atom, and r_ij the atomic distance between the marked atom i and j-th atoms. Both equations were almost equal in accuracy. Similar correlations were also found for the binding energies of O_1S and N_1S.

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The effects of the pretreatment of spectral data on the predictive precision and the optimal number of factors were studied for PLS1 quantitative analysis. For simulated spectral data of a two-component mixture system, the effectiveness of mean centering and/or scaling, and of selection of the spectral-data region was examined with and without a constraint in concentrations. Our conclusions are: (1) no scaling is necessary for the spectral data; (2) centering reduces the number of optimal factors by one or two; (3) when there is no constraint, centering is not always required; (4) selection of the spectral region is dependent on the signal-to-noise ratio of the waveform.

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A highly sensitive spectrophotometric determination (Δε=ε_blank-ε_sample=3.0 ×10⁵l mol^-1 cm^-1) for nitrite ion using 5, 10, 15, 20-tetrakis(4-aminophenyl)porphine (TAPP) was developed. This method is based only on the formation of the diazonium salt. Recommended procedure: A 2.0 ml aliquot of 10^-5 mol/l TAPP solution and 2.5 ml aliquot of 1.0 mol/l HCl were mixed, the sample solution containing nitrite ion added and the volume then made up to 25 ml with water. After 30 min at 30°C, the absorbance at 434 nm was measured. The determination range was 1.0 × 10^-84.0× 10^-7 mol/l (0.4618 ppb) and the detection limit (S/N= 3) was 4.0 × 10^-9 mol/l (0.18 ppb). The relative standard deviation of the median was 1.03% (10 determinations). This simple method will be applicable to various assays such as environmental analysis and clinical diagnosis.

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Molecular weight averages of four polystyrenes (PS) and two poly(methylmethacrylates) (PMMA) were determined by size exclusion chromatography at 26 laboratories belonging to the section of special study on SEC. Polymer standards for constructing a calibration curve were delivered to the laboratories. Sample concentrations, the injection volume and the procedure for drawing the baseline were prescribed. Other experimental conditions were the same as in the previous report. Relative standard deviations (RSD) of over-all mean molecular weight averages were as follows after rejecting the suspected result in each set of data:13.715.8% for PS number-average; 5.05.8% for PS weight-average; 11.913.3% for PMMA number-average; and 10.911.3% for PMMA weight-average. Compared with the results for the former round robin test, RSD was not improved much because the procedure for drawing the baseline was not restricted strictly.

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We evaluated a new gel filtration column and eluent commercially available under the trade-names of TSKgel Lipopropak and TSKeluent LP-1 for the analysis of serum lipoproteins. Lipoproteins were separated within about 20 min, and were detected by post column reaction using the cholesterol oxidase-peroxidase system. Total and high density linoprotein(HDL) cholesterols could be auantified every 10 min, with high recovery and high reproducibility.

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