The magnetic chromatography of magnetic fine particles has been proposed using a periodically intermittent magnetic field. A separation column packed with magnetically permeable steel beads is inserted into the center hole of an electromagnetic coil. The steel beads are coated with a polytetrafluoroethylene film, and the column is vibrated atca. 10Hz in order to minimize any irreversible adsorption of the magnetic particles on the beads. Ethanol is used as a mobile phase, and the iron oxide magnetic particles in the mobile phase are continuously monitored by flame atomic absorption spectroscopy. An elution peak for magnetite particles is delayed with increasing coil current and loading ratio of the magnetic field, while that for hematite particles is not influenced by the magnetic field. The effects of various parameters on the retention time for the magnetite particles are discussed from a theoretical viewpoint.

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Reactive pyrolysis-gas chromatography (Py-GC) in the presence of tetramethylammonium hydroxide (TMAH) was successfully applied to the compositional analysis of cationic polyacrylamide (PAAm) resins, prepared from acrylamide (AAm) and dimethylaminoethylmethacrylate (DM). The reactive pyrolysis of cationic PAAm resulted only in hydrolysis of ester linkages in DM units and did not lead to subsequent methylation of hydrolyzates and cyclization. The intense peak of 2-(dimethylamino)ethanol formed from DM units through the reactive pyrolysis was used as the key peak for the determination of DM content. The content of DM units in the cationic PAAm samples was determined with a precision of about 4% of relative standard deviations.

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Gas chromatographic determination of C₂₇-bile acids was investigated for the study of bile acid biosynthesis and related congenital disorders. The intermediate C₂₇-bile acids in the β-oxidation step and related compounds were conveniently synthesized from the corresponding C₂₄-bile acids as standard samples. The separation of methyl ester-trimethylsilyl ether (Me-TMS) and methyl ester-dimethylethylsilyl ether (Me-DMES) derivatives of the C₂₇-bile acids was carried out by capillary gas chromatography. Then methylene units of the above derivatives were measured. The Me-DMES derivatives were more efficient for the separation of C₂₇-bile acids than the Me-TMS derivatives. The calibration curves for the Me-DMES derivatives of C₂₇-bile acids showed good linearities over the range of 5-200ng; the detection limits were ca. 0.5ng (S/N=5). The relative recoveries from biological samples were 93-105% for all C₂₇-bile acids using 24- nor-chenodeoxycholic acid as an internal standard. An application to the diagnosis of Zellweger syndrome is also discussed.

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A highly sensitive and specific method was established for quantification of 3β-hydroxy-5-cholenoic acid by high- Performance liquid chromatography using an immobilized -β-hydroxysteroid dehydrogenase column (β-HSD column) and a postcolumn fluorescent detection. The β-HSD column shows maximum enzyme activity and stability at 20°C, and has a very short life at 25°C. The detection limit was 7pmol/injection. We also developed an efficient method for extracting the sulfate conjugates at position 3 from urine and conducting their enzymatic hydrolyses. This method was used to analyze urine from patients with congenital biliary atresia. A high concentration of 3β, 12α-dihydroxy-5- cholenoic acid was also present in the urine from these patients.

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A highly sensitive chemiluminescence assay system for human chorionic gonadotropin (hCG) and thyroid stimulating hormone (TSH) was developed using a newly synthesized acridinium ester (AE) with a binding substitutional group at the N-10 position and having excellent chemiluminescence and stability. AE-labeled antibodies with an excellent chemiluminescence intensity were prepared after studying the labeling of anti-hCG antibodies with AE under different conditions. By studying the purification conditions for AE-labeled antibodies we produced AE-labeled antibodies having a low background value when assayed. When the detection limit is defined as the signal value+3SD at a concentration of zero for each substance measured, the detection limit for hCG is 0.01IU/l and that for TSH is 0.001μIU/ ml, demonstrating extremely high sensitivity. The labeled antibody′s stability is also excellent.

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Intensities of the analyte and the two kinds of system peaks in ion-exchange chromatography with bulk-property detectors, such as conductivity detector and UV absorbance detector in indirect mode, were investigated theoretically and experimentally. Extensive computer simulations of the chromatographic processes, not only for monobasic acid eluent systems but also for dibasic strong-acid eluent systems, were performed first. Then, the functional relationships between the peak intensity and chromatographic parameters (the acid dissociation constant, the eluent concentration, the eluent acidity, the acid-partition coefficient, etc.) were derived, and confirmed experimentally. The peak intensity variation previously observed for common anions with the Tiron eluent has been explained clearly. There are two kinds of sensitivity enhancement in conductivity detection when the retention volume of the 2nd system peak is larger than that of an analyte peak (k′_X<k′₂). Both are caused by the acid partition phenomenon. One depends essentially on the chromatographic processes and becomes larger when k′₂ is close to k′_X. The other is simply explained by the stoichiometric and equilibrium considerations on the chemical reactions in a column. These two kinds of enhancement are additive. With an acid eluent and conductivity detection, the intensity of analyte peaks is remarkably enhanced. This sensitivity increase is very useful in the practice of non-suppresser IC. Moreover, the first system peak is very small with acid eluents. This is advantageous for the detection of the species of low retention.

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An Eosin Y-containing liposome solution as a sample was for the first time migrated and detected by capillary zone electrophoresis with chemiluminescence detection using a peroxyoxalate system. Two peaks, as a typical example, were recorded on the electropherogram: the first one was due to Eosin Y entrapped in liposome; the second one was due to free Eosin Y in the bulk solution. The electropherogram, comprising two peaks, readily, rapidly, and sensitively offered various forms of information about the liposome, including the preparation course, stability, permeability, and surface charge. Furthermore, an Eosin Y-containing liposome solution gave a good linear relationship between the concentration and chemiluminescence intensity. Only the chemiluminescence detection was effective for examining the electrophoretic behavior of the Eosin Y-containing liposome in a capillary. Spectrophotometric and fluorescent detectors could not be utilized for detecting the liposome, due mainly to the low sensitivities.

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Semiconductor laser-induced fluorescence detection of native (target) DNA has been accomplished by free-solution capillary electrophoresis (CE) using an oligonucleotide labeled with a cyanine dye as a DNA probe. A mixture of probe DNA and target DNA, which is complementary to probe DNA, is incubated to form hybrid DNA; the mixture is then injected into a capillary. Single-stranded probe DNA and double-stranded hybrid DNA were separated by free-solution CE. A 19mer oligonucleotide labeled with fluorescein isothiocyanate (FITC) was used as probe DNA in a preliminary study. The stability of double-stranded DNA during migration was evaluated by changing the temperature of the solution in the capillary, i.e. the applied voltage in CE. The dissociation of double-stranded DNA was appreciable at high applied voltages. Thus, suppressing the temperature in the capillary, i.e. optimization of the voltage, was required in order to prevent the dissociation of double-stranded DNA. Furthermore, a new labeling reagent, a cyanine derivative, was synthesized in order to be applied to semiconductor laser-induced fluorometry. The detection limit was 8×10^-9M for probe DNA.

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A flow injection (FIA) determination of hydrogen peroxide (H₂O₂) was developed by using chemiluminescence (CL) reaction of bis(2, 4, 6-trichlorophenyl)oxalate (TCPO) in an oil/water (O/W) emulsion system composed of ethyl acetate, non-ionic surfactant polyoxyethylene(20) sorbitane monolaurate (Tween 20) and water. The intensity of the light emitted from the CL reaction is proportional to the concentration of H₂O₂. A linear calibration graph was obtained over the H₂O₂ concentration range 1×10^-6-1×10^-3mol dm^-3. The relative standard deviations of 3.4 and 3.6% were obtained for five determinations of 1×10^-5 and 1×10^-6mol dm^-3 of H₂O₂, respectively. The present method was applied to the determination of L-glutamic acid in culture medium, which was based on the detection of H₂O₂ produced from glutamic acid in the immobilized glutamate oxidase reactor in the flow system.

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A flow injection system for the potassium speciation in fortified wines, using two detectors placed in series, is described. The free, or ionized form, is monitored in a tubular-shaped potassium ion-selective electrode, and the total potassium content in a flame emission spectrometer used as end-of-line detector. Potassium determinations can be carried out in a linear range from 300 to 2000mg l^-1, with a sampling-rate of 60 samples per hour. The results obtained were comparable to the conventional procedures using the same detection systems, and the precision was good (relative standard deviations below 3.1% for free potassium and 3.8% for total potassium).

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A study was made of the calculation methods which give an accurate purity value when the purity is measured with a mixture which forms an eutectic mixture. It was revealed by a comparison of the purity values obtained by various measurement methods using DSC that those obtained by the stepwise method are more accurate than those obtained by other methods. Aiming to apply the advantages of the stepwise method to the dynamic method, the following improvements were made. The total heat of fusion was measured inclusive of the eutectic peak. To calculate the melt fraction, the total heat of fusion was regarded as extending up to the inflexion point at the end of the peak. Furthermore, the melt fraction was calculated assuming the heat up to each temperature to be the partial heat of fusion. A van′t Hoff plot was assumed starting with a point 5% below the principal component peak following the end of the eutectic mixture′s peak and ending at the inflexion point. An analysis using the improved method excludes any bias, and the obtained value was highly reliable. A 95mol% pure sample gave a measurement with an error within 0.5mol% or less.

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A catalytic spectrophotometric method for the determination of traces of tungsten(VI) is proposed. In the presence of iron(II), chlorpromazine (CP) is oxidized by hydrogen peroxide in a hydrochloric acid solution to form a red free radical, which is further oxidized to a colorless compound. The reaction can be followed by measuring the increase in absorbance of the red free radical at 525nm; the maximum absorbance is obtained on an absorbance/time curve at a given reaction time. Tungsten(VI) inhibits the color formation and the maximum absorbance value decreases with an increase in the tungsten(VI) concentration. Thus, the maximum value is used as a parameter for the tungsten(VI) determination. Under the optimum experimental conditions (7.6×10^-2M hydrochloric acid, 4.9×10^-3M hydrogen peroxide, 2.5×10^-4M CP, 1.4×10^-4M Iron(II), 35°C), tungsten(VI) can be determined in the range from 2 to 500μg l^-1. The relative standard deviations are 0.7, 0.2 and 1.7% for 100, 20 and 6μg l^-1, respectively. This method was successfully applied to a determination of tungsten(VI) in hot spring water samples.

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The response of an iridium oxide (IrO₂) pH-sensor (nonaqueous version of METOX, TOA Electronics Ltd.) was studied in various dipolar aprotic solvents. From the potential measurements in picric acid-picrate solutions, it was confirmed to respond in a Nernstian way to the pH in all the solvents studied. The response speed of the IrO₂ pH-sensor was compared with that of the glass electrode as well as those of the Si₃N₄- and Ta₂O₅-type pH-ISFETs, carrying out acid-base titrations at various speeds of titrant addition. The response speed of the IrO₂ pH-sensor was much higher than that of the glass electrode, though it was somewhat lower than those of the pH-ISFETs. The IrO₂ pH-sensor responded in a wide pH range, gave reproducible results, needed no pretreatment, and was durable over a year. It is promising for pH measurements in various nonaqueous solutions free from redox systems.

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A method for the determination of Pb, Cu and Se in tobacco samples by anodic stripping voltammetry has been developed. Pb, Cu and Se were determined in Turkish and American cigarettes using a mercury film graphite electrode, by digesting the tobacco sample in acid or acid mixtures following extraction with 1-butanol. The appropriate results for Pb, Cu and Se were obtained from the digestion mixtures of HNO₃-HclO₄ (1/1) for Pb, HNO₃-HClO₄-H₂SO₄ (2/2/1) for Cu and Se. Interference due to the large amount of Cu was reduced to the proper level by 1-butanol extraction, that made the determination of Se possible. The effects of deposition potentials, deposition times and pH of the medium have been discussed. The applied deposition potentials for Pb, Cu and Se were -850, -600 and -400mV (vs. Ag/AgCl) respectively. The peak potentials in HClO₄ solution (pH≅2) were -350mV for Pb, -20mV for Cu and +60mV for Se. The relative standard deviations are 4.5% at the concentrations of 2.2ppm Pb (n=5) and 4.4ppm Cu (n=6), and 8.3% at 0.12ppm Se(IV) (n=8).

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Inductively coupled plasma mass spectrometry (ICP-MS) is applied to geological standard rocks for the determination of Y, lanthanoids (Ln′s), Th and U. Internal standardization is employed for the precise measurement: Rh for Y, In and Tl for Ln′s, Bi for Th and U. For Ln′s, linear interpolation correction is used. Our ICP-MS data agree with the recommended values within 10% for most samples. Their chondrite-normalized Ln abundance patterns are smooth, suggesting that our ICP-MS data are highly accurate and can be used for discussing detailed abundances of Ln′s. The Y, Th and U data are as precise as the Ln data. The simultaneous and precise determination of Ln′s, Th and U enable us to extend the geochemical discussion in better detail than before.

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Measurements of ²¹⁰Pb (half life of 22.3 y) at various depths down to 180m in an ice core from an Arctic glacier, Åsgårdfonna, in northern Spitsbergen have been made. The activity of ²¹⁰Pb was obtained by counting α-rays from its daughter nuclide, ²¹⁰Po (half life of 138d). The specific activity of ²¹⁰Pb at the surface of the glacier, 110mBq/kg, decreased exponentially with depth to 4.72mBq/kg at about 30m depth. Below 30m, the activities were nearly constant and the average value from 30m to 180m was 4.85±1.33mBq/kg. This result indicates that the atmospheric ²¹⁰Pb deposit onto the glacier decays as a function of time at a rate controlled by its half life. The α spectrometric method for the determination of ²¹⁰Pb in an ice sample and the result of the ice core dating are described in this paper.

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The absorption spectra of phenolphthalein (H²PP) in phosphate buffers of pH 5 to 13 were analyzed in order to determine the features of the dissociation and coloration of H²PP. The spectra demonstrated that HPP^-, while keeping a γ-lactone ring, was colorless, and that only PP^2- was red, where pK₁=9.05, and pK₂=9.50; further, the reaction of hydroxide ion with PP^2- to produce colorless PP(OH)^3- was rather slow, where pK₃=12. On the contrary, the color of the aqueous solution of phenolsulfonphthalein (H₂⁺PS^-), having a zwitter ion structure and no lactone ring, was orange-red, which dissociated to yellow HPS^- and finally to PS^2-, having a similar red color and absorption spectrum to PP^2-. These results clearly demonstrate the relationship between the color and the prolonged conjugated system.

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The extraction behavior of Al(III), Ga(III) and In(III) was investigated using bis(1, 1, 3, 3-tetramethylbutyl)phosphinic acid (MBP) and its sulfur analogues, bis(1, 1, 3, 3-tetramethylbutyl) monothiophosphinic acid (MTP) and bis(1, 1, 3, 3-tetramethylbutyl)dithiophosphinic acid (DTP) as extractants. A typical chelate extraction behavior was observed in these extraction systems in the pH range examined. The degree of extraction was in the order of In(III)>Ga(III)>Al(III). Moreover, the ability of extractants for mutual separation of these metals from one another decreased in the following order: DTP>MTP>MBP. The quantitative mutual separation of these metals can be achieved using DTP/hexane with single extraction. In the higher HCl concentration range, however, slight extraction of Ga(III) and In(III) was observed; this is due to the extraction of GaCl₄^- and InCl₄^- pairing with the protonated extractants.

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Zirconium phosphate, HZr₂(PO₄)₃ (NZP), in a powder form was synthesized from zirconium chloride oxide and sodium dihydrogenphosphate, and its ion exchange adsorption properties to alkali metal ions were studied. The ion-exchange adsorption partition coefficients of NZP to alkali metal ions at pH=3.4 were found to be 3.2×10³(Li⁺), 4.5×10⁵(Na⁺), 2.6 (K⁺), 12 (Rb⁺), and 380 (Cs⁺) cm³ g^-1. The results indicate that NZP has a high adsorbability to sodium ions. Mixed granules of NZP and silica sol (NZP-P) were then prepared and applied for the selective removal of sodium ions by a column adsorption method.

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An extractive spectrophotometric method for the determination of micro amounts of ascorbic acid has been developed by exploiting its reducing nature. Iron(III) is converted to iron(II) by the addition of ascorbic acid, which forms an extractable yellow-colored complex with picolinic acid and pyridine. The absorbance is measured at 400nm. Beer′s law is obeyed in the concentration range 0.4-5.6μg ml^-1. This method has been satisfactorily applied to the analysis of a variety of samples, including pharmaceuticals, food products and biological fluids.

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Palladium(II) reacts with halogenide ions, such as chloride ion and bromide ion, to form anionic complexes. The cetylamino groups of chitin are protonated in an acidic medium, acting as an anion exchanger. The property of chitin was applied to the preconcentration and microdetermination of palladium(II). The palladium(II) chloro complex was quantitatively adsorbed onto chitin over the pH range of 2.5-4.0. The chitin which adsorbed the palladium(II) was separated from the sample solution by a membrane filter, and dispersed in pure water. The resulting suspension was introduced directly into a tungsten metal-furnace atomizer. An ashing temperature of 1000°C and an atomizing temperature of 2300°C were selected. The detection limit for palladium(II) was 0.06μg/100cm³ (S/N_??_3). The proposed method was applied to the determination of trace amounts of palladium(II) in water samples.

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A method for the determination of trace amounts of molybdenum at ng l^-1 levels in rainwater and snow is described. Molybdenum is extracted into xylene as a complex of N-benzoyl-N-phenylhydroxylamine (BPA), and subsequently back- extracted into 100μl of nitric acid for a determination by graphite-furnace atomic absorption spectrometry (GFAAS). The extraction and micro-volume back-extraction allows molybdenum to be concentrated about 6000-fold. The back- extracted solution is suitable for the determination of molybdenum by GFAAS. The conditions of extraction and back- extraction, such as acidity, concentration of BPA, and amount of nitric acid, were investigated. The detection limit for molybdenum is 0.54ng l^-1 based on a 1700-fold preconcentration. The application of this method to the determination of molybdenum in various samples of rain-water and snow is demonstrated.

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A method for determining trace amounts of silver in high-purity aluminum is described. Silver in an aluminum solution is extracted into xylene as its diethyldithiocarbamate (DDC) complex, and subsequently back-extracted into 200μl of nitric acid for a determination by graphite-furnace atomic absorption spectrometry (GFAAS). Silver can be completely extracted from an aluminum solution into xylene over a pH range of 2.5 to 4, and for a DDC concentration of over 4×10^-3mol l^-1. The resulting solution, back-extracted with nitric acid, is suitable for the determination of silver by GFAAS. The detection limit for silver was found to be 1.4ng g^-1 when 0.2g of an aluminum sample is used. The application of this method to the trace analysis of silver in high-purity aluminum samples is demonstrated.

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Lanthanoid elements in hard tissue (shell and pearl) of shellfish were determined and their distributions were examined by ICP-MS. The ICP-MS signals for Lanthanoids contained in these samples were highly suppressed by coexisting calcium, the macro-component, which made the determination of lanthanoids difficult. To resolve this problem, we applied the coprecipitation method with ferric hydroxide to separate the lanthanoids from the interfering element, calcium. All the lanthanoids were coprecipitated quantitatively and separated at pH 9. Pearl and shell samples were dissolved in inorganic acids and filtered, then the 14 lanthanoid elements in the sample solution were simultaneously determined. The lanthanoids contents in hard tissues ranged from 0.25 to 82ppb in Akoya-gai of seawater shellfish, and from 0.3 to 72ppb in the Ikecho-gai of Lake Biwa. It was found that the distribution of lanthanoid elements in these samples followed the Oddo and Harkins law.

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