A rapid field scan L-band electron spin resonance computed tomography (ESR-CT) system has been developed in order to obtain three-dimensional images of the distribution of free radicals in a sample. The ESR system comprises an L-band (ca. 700MHz) ESR spectrometer, an air-core electromagnet equipped with a field-scanning coil, three field-gradient coils, and a microcomputer. The rapid field scan (15mT/s) causes a delay in the magnetic-field strength due to eddy-current losses. However, it was found that the magnetic field strength could be corrected by a simple mathematical equation related to a low-pass filter model. Using this system, the original ESR data used to obtain one three-dimensional ESR-CT image could be obtained in 150s. The time course of the ESR-CT images of the test sample containing the reaction of nitroxide radical with ascorbate ion has been shown as an example of a spatiotemporal measurement.

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In vivo ¹¹B NMR spectra of plant tissue, namely, radish roots, apple fruit, cabbage leaves and komatsuna plant leaves and roots, were successfully obtained. In the spectra, the signals of borate monoester and diester, together with boric acid, were observed, which shows that the in vivo ¹¹B NMR technique provides direct evidence that the borate esters exist in plant tissue. The spectra of juice and residue prepared from radish roots and apple fruit revealed that the signals, especially those of borate esters, in the intact plant spectra were derived from the water-soluble fraction in the plant cell.

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As novel calixarene or macrocyclic types of extractants, 37, 38, 39, 40, 41, 42-hexakis(carboxymethoxy)-5, 11, 17, 23, 29, 35-hexakis(1, 1, 3, 3-tetramethylbutyl)calix[6]arene and 25, 26, 27, 28-tetrakis(carboxymethoxy)-5, 11, 17, 23-tetrakis(1, 1, 3, 3- tetramethylbutyl)calix[4]arene as well as p-(1, 1, 3, 3-tetramethylbutyl)phenoxy acetic acid, as their monomeric analog, and 2, 6-bis[2-carboxymethoxy-5-(1, 1, 3, 3-tetramethylbutyl)benzyl]-4-(1, 1, 3, 3-tetramethylbutyl)phenoxyacetic acid as a linear trimer analog, have been synthesized in order to investigate their extraction abilities of rare earth metal ions, RE³⁺ (RE=Y, La, Pr, Nd, Sm, Eu, Gd, Ho, Er), from an aqueous nitrate solution. It was found that the calixarene derivatives provide much higher extractability and greater separation efficiency than do the monomeric analog and the other acidic carboxylate extractants. The selectivity for rare earth elements in this system is not affected by the ring size. In extraction from an aqueous mixture of nitric acid-glycine, the stoichiometry of the extracted species was determined and the extraction equilibrium constants as well as the separation factors were evaluated for each extractant. A stripping test was also performed and the stripping of rare earths was found to be successfully achieved with diluted hydrochloric acid.

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The kinetics of the complexation reaction of zirconium(IV) and hafnium(IV) with Semixylenol Orange (H₄L) have been studied spectrophotometrically by means of a stopped-flow technique. The rate of formation of the complex is expressed as d[MHL⁺]/dt=k₁[M⁴⁺][H₅L⁺][H⁺]^-2+k₂[M⁴⁺][H₅L⁺][H⁺]^-3-k₃[MHL⁺][H⁺]-k₄[MHL⁺][H⁺]² for both metal ions (M⁴⁺). With values of k₁ and k₂, assuming a dissociative interchange mechanism for the first two reaction paths in this rate equation, the rate constants of the loss of coordinated water molecules at MOH³⁺ and M(OH)₂²⁺ were estimated. With these rate constants, the γ parameters for both metal ions, which describe the acceleration effect of the bound ligand A (A=OH^- in this study) on the water exchange rate at MA, were also estimated. With the same parameter, some possibilities to design a new kinetic-catalytic method of analysis based on ligand-substitution reactions involving zirconium(IV) were proposed.

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The extraction chromatographic behaviors of zirconium(IV) and hafnium(IV) were investigated using dibenzyl sulfoxide (DBSO) and petroleum sulfoxide (PSO) as stationary phases in the media of hydrochloric acid and hydrochloric acid- ammonium thiocyanate by the batch method. In both systems, Zr(IV) and Hf(IV) showed almost the same behavior at higher HCl concentration due to the formation of halo metal acids, H₂ZrCl₆ and H₂HfCl₆. In the PSO-HCl-NH₄SCN system, the distribution ratios of Zr(IV) and Hf(IV) gave greater values, owing to the formation of ZrO(SCN)₂ and HfO(SCN)₂ at a lower HCl concentration and a decrease along with an increase in the HCl concentration; such phenomena were not observed in the DBSO-HCl-NH₄SCN system. The IR spectra of the extracted complexes gave evidence of oxygen in an SO group coordinating Zr(IV) or Hf(IV) to form extractable species. Finally, a quantitative separation of Zr(IV) and Hf(IV) was achieved using a PSO-extraction chromatographic column (φ6×220mm) at 25°C.

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A new liquid chromatographic method for the determination of acid dissociation constants is presented on the basis of theoretical equations regarding the effect of background mobile phase ions on the retention of ionic analytes on nonionic polymer packings. The dissociation constants determined by the present method using Bio-Gel P-2 and Toyopearl HW- 40S as the column packings and water as the mobile phase solvent were in fairly good agreement with the values obtained by potentiometry. This method has an important advantage of permitting the simultaneous determination of thedissociation constants and the charges of analyte compounds. One can then readily assign a dissociation constant obtained for a polybasic acid to the corresponding step of the proton dissociation.

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The origin and characteristics of the system peaks appearing in ion chromatography with dibasic acid eluent systems were extensively studied by computer simulation, theoretical considerations, and experiments. The functional relationships between the retention volume of the second system peak and chromatographic parameters have been derived for dibasic acid eluent systems. The functional relations reproduced the results by computer simulation of the chromatographic processes for dibasic acid eluent systems based on the plate theory and multiple chemical equilibria in each theoretical plate. Sample injection perturbs not only the partition equilibrium of the eluent acid between the mobile phase and the stationary phase, but also the concentration ratio of monovalent and divalent eluent ions on the ion-exchange site in the stationary phase. Therefore, the second system peak is caused mainly by the perturbation of the partition of the acid molecules in dibasic acid eluent systems, as in monobasic acid eluent systems. In addition, the ion-exchange reaction between HB^- and B^2- is another cause of the second system peak in dibasic acid eluent systems. The retention volume of the second system peak has been explicitly related to the elution parameters. The complicated retention of the second system peak observed by Jackson and Haddad with phthalate eluent was elucidated for the first time. By using the derived functional relationships, we can easily obtain the partition isotherm for the eluent acid from the retention volume data of the second system peak in the chromatographic measurements.

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The aim of this paper is to examine the precision of fluorometry on the basis of a recently proposed theory to predict the relative standard deviation (RSD) of measurements from signal and noise in an analytical instrument. According to the theory, the instrumental baseline drift which is often formulated as 1/f noise can well be approximated by a mixed random process of white noise and the Markov process. The standard deviations (SD), w, of the white noise and the SD, m, and auto-correlation parameter, ρ, of the Markov process can be parametrized from the power spectral density of the blank line drift by the least squares curve fitting. All the parameters necessary for the uncertainty prediction (w, m, ρ, signal domain, (k_c+1, k_f) and signal area, A, over the domain), can be determined directly and uniquely from experiments and experimental design. No arbitrary constants are involved in the prediction theory. The uncertainty prediction is shown to be superb over a wide concentration range of Rhodamin B in the fluorescence measurement. The influence of the integration domain on the precision is considered.

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γ-Cyclodextrin with a sodium anthranilate moiety (1) has been prepared as a sensing molecule for organic compounds including terpenoids and bile acids. The sensing and host-guest complexation properties are discussed here in comparison with those of β-cyclodextrin with a sodium anthranilate moiety (2) and γ-cyclodextrin with two sodium anthranilate moieties (3). Compound 1 shows a pure monomer fluorescence with an intensity which increases upon the addition of guest species. The extent of fluorescence variation with a guest is used to determine the sensing factor (ΔI/ I⁰) of 1 for a guest. Compound 1 recognizes terpenoids better than 3 and bile acids better than 2.

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A microbial sensor based on an oxygen electrode and the microorganism Pseudomonas putida was developed in order to determine fixed acids, such as L-malic acid, succinic acid and L-lactic acid, in wine. The carbon source used in cultivating the microorganism affected the selectivity of the sensor to a great extent. When _L-lactic acid was used as the carbon source, the microbial sensor gave a selective response for L-lactic acid. A flow injection analysis (FIA) system for determining L-lactic acid was constructed and applied to commercially available wine samples. The obtained result was comparable to that obtained by the F-kit method. On the other hand, the microbial sensor showed a response for L-malic acid, L-lactic acid, succinic acid and ethanol present in wine when meso-tartaric acid was used in the cultivation. The addition of L-lactic acid (0.05mM) and ethanol (0.01%) into the carrier solution suppressed the response for L-lactic acid and ethanol, and under the conditions the microbial sensor was thus selective for L-malic acid and succinic acid. The sensor responses for wine samples (n=6) were linearly related to the sum of the L-malic acid and succinic acid concentrations determined by HPLC with a correlation coefficient of 0.969.

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The voltammetric behaviors of dopamine (DA) and ascorbic acid (AA) at a glassy carbon (GC) electrode anodized in 1, ω- alkanediol were examined. On cyclic voltammetry (CV) at a 1, 5-pentanediol-modified GC electrode, the electrode process of AA was totally depressed, while DA still showed an anodic peak. Although similar phenomena were observed at a GC electrode anodized in 1, 3-propanediol or 1, 4-butanediol, the 1, 5-pentanediol-modified electrode suppressed the anodic peak of AA most strongly. The voltammetric response of DA at the modified electrode was enhanced by the presence of AA, and the extent was controllable by a proper selection of the sweep rate. Thus, the electrochemical detection of DA with high sensitivity was achieved through CV with 0.1V s^-1 at the modified electrode by adding excess AA, while electrochemical discrimination of DA from excess AA was realized at 20V s^-1.

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A method for simultaneous determination of 26 halogenated volatile organic compounds (VOCs) in air is developed. In order to determine a large variety of volatilities of halogenated VOCs, a collection tube packed with two layers of activated carbons (Carbosieve S2 and Carbopack B) was adopted for air sampling and a tube packed with Carbopack B (with a length of 50mm) was adopted for a trap tube of the TCT (thermal desorption and cold trap) injection system. The total recoveries of the method were examined under several conditions. Twenty six kinds of halogenated VOCs were recovered with more than 80% yield under conditions of 20°C, relative humidity of 80-100% and induced air volumes of 10-30l: the recovery ratios were 89-113% and the relative standard deviations were 1.7-8.8% in the case of the induced air volume of 20l. Under a condition of 40°C and induced air volume of 20l, the recovery ratios of these VOCs, except CFC-12, were 63-119%: the recovery ratio of CFC-12 ranged 98-12% in the case of induced air volumes of 5-20l.

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Preconcentration of cobalt(II) and nickel(II) as the 1-nitroso-3, 6-disulfo-2-naphtholato [nitroso R (NR)] complexes onto chitin powder has been applied to the sub-μg/l level determination of their ions in water samples by tungsten metal furnace atomic absorption spectrophotometry. The cobalt(II) and nickel(II) as NR complexes (Co•NR, Ni•NR) were quantitatively adsorbed onto chitin at pH 4.0-6.0 for Co•NR and pH 5.0-7.0 for Ni•NR. The Co•NR and Ni•NR adsorbed chitin was separated from the sample solution by membrane filtration, then dispersed in water. The resulting suspensions were injected directly into the tungsten metal furnace. The detection limit (S/N=3) for cobalt(II) was 0.02μg/500cm3 and that for nickel(II) was 0.03μg/500cm³.

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In order to correct the variation of aerosol density in laser ablation/inductively coupled plasma mass spectrometry, a laboratory-made laser light-scattering cell was inserted into the aerosol transport tube between the laser ablation system and the torch. The temporal variation of signals from the laser light-scattering cell correlated well with that of the ion signals from the mass spectrometer. The precision of ion intensity measurement corrected with the laser light-scattering method was improved to the same level as that attained with the conventional internal standard method even in the single pulse mode.

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In the determination of an acid value of colored and/or turbid edible oil by chemiluminescence measurement, the chemiluminescence signal is reduced by an inner-filter effect of the sample solution, which leads to a sizable measurement error. To remove this inner-filter effect, we propose a photometric correction scheme that utilizes the sample transmittance as an additional parameter to obtain the true chemiluminescence signal. To this end, a new chemiluminometer that detects simultaneously both the chemiluminescence and the transmittance signals is presented. The performance of the proposed chemiluminometer was evaluated by the chemiluminescence of a turbid luminol-H₂O₂ solution. The experimental results show the effectiveness of the proposed chemiluminometer in determining the true chemiluminescence signal even in the presence of strong inner-filter effect. Using this chemiluminometer, the relationship between chemiluminescence intensity and the acid value of edible oil (rape-soybean oil) was investigated. The results indicated that the corrected chemiluminescence intensity increased rapidly as the oil oxidation progressed, while the observed chemiluminescence intensity was misleadingly reduced by the strong inner-filter effect.

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A flow injection analytical method using a walljet-type electrochemical detector was developed for determining the content of free fatty acids. A simple flow injection system was constructed. An ethanol solution containing 3mM 2-methyl-1, 4-naphthoquinone and 38mM LiClO₄ served as the carrier solution. The flow-signal response for higher fatty acids was linear between 25 and 1500pmol test^-1. The free fatty acid content in various fat and oil samples was determined by both the present and conventional titration methods. The present method was found to be not only highly sensitive with high reproducibility, but also quite simple and rapid.

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The relationship between the enantioselectivity and association constants of enantiomers on high-performance liquid chromatography with a protein-conjugated chiral stationary phase (CSP) was investigated using a flavoprotein- conjugated CSP, with ketoprofen (KP) as a model drug. The association constants of the enantiomers for native flavoprotein were different; it has been found that they contribute to the chiral separation on a protein CSP. Equations including the association constants were developed to calculate, the capacity factors and enantioselectivities on protein CSPs; they were validated by means of experiments using a flavoprotein column in combination with variable numbers of non-specific columns in series. The capacity factors and enantioselectivities calculated with the developed equations showed reasonable agreement with those obtained by chromatography employing a conventional flavoprotein column (150mm×4.6mm i.d.) with a mobile phase containing methanol as an organic modifier. Our results imply that protein- conjugated CSPs are complex-stationary phases consisting of both a specific phase for chiral separation and a non-specific phase, and that the resolution of the enantiomers depends upon the balance of interactions of solute molecules with the two phases.

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A high-performance liquid chromatographic method with fluorescence detection was described for the determination of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). 2-(4-Hydrazinocarbonylphenyl)-4, 5-diphenyl- imidazole (HCPI) was used as a fluorescent label. The derivatization of EPA and DHA with HCPI was performed in 20min at room temperature in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and pyridine as condensing agents. The HCPI derivatives separated on an ODS column by a gradient elution were detected at 455nm with an excitation at 335nm. The calibration curves for both EPA and DHA were linear over the range 1-600pmol per 20-μl injection (r>0.999 for both acids). The detection limits for EPA and DHA were 200 and 190fmol, respectively, at a signal-to-noise ratio of 3. Relative standard deviation of the peak height for seven replicate measurements of these fatty acids were ca. 2%. EPA and DHA were successfully determined in human serum, dietary supplements and a pharmaceutical preparation by this method.

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In order to correct the variation of aerosol density in laser ablation/inductively coupled plasma mass spectrometry, a laboratory-made laser light-scattering cell was inserted into the aerosol transport tube between the laser ablation system and the torch. The temporal variation of signals from the laser light-scattering cell correlated well with that of the ion signals from the mass spectrometer. The precision of ion intensity measurement corrected with the laser light-scattering method was improved to the same level as that attained with the conventional internal standard method even in the single pulse mode.

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