The mutual separation of heavy lanthanoid elements and yttrium was performed by high-speed countercurrent chromatography (CCC) provided with a multilayer coiled column containing a toluene solution of 2-ethylhexyl- phosphonic acid mono-2-ethylhexyl ester. The rare-earth elements were chromatographically eluted by a mobile phase with a stepwise gradient of the acid concentration. The separation of rare-earth elements including yttrium after continuous-flow enrichment into the stationary phase from a large volume of a sample solution was also accomplished with sufficient resolution.

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The ion-transfers of sodium and potassium cations, facilitated by naptho-15-crown-5, N15C5, were studied at an interface between water and nitrobenzene using current-scan polarography. A polarographic wave caused by the facilitated transfer of sodium cation was observed under the condition that the concentration of sodium cation was much higher than that of N15C5, [Na⁺]_??_[N15C5]. It is inferred from an analysis of the wave that a sodium cation trasfer is facilitated due to the formation of a 1:1 complex of metal-to-ligand ratio, Na(N15C5)⁺. However, since no wave was observed under the condition [N15C5]_??_[Na⁺], a 1:2 complex may not exist in this condition. On the other hand, since a clear facilitated wave of potassium cation was only obtained under the condition [N15C5]_??_[K⁺], the transfer of a 1:2 complex, K(N15C5)₂⁺, is inferred. Since an indistinct wave overlapped by an anodic final current rise in [K⁺]_??_[N15C5] appeared, a small stability of a 1:1 complex, K(N15C5)⁺, is expected. Considering the EC mechanisms for those transfers, the stability constants of those complexes in the nitrobenzene phase were determined. The values are 5.0×10⁶M^-1 for Na(N15C5)⁺ and 6.0×10⁸M^-2 for K(N15C5)₂⁺ These results are quite consistent with the results from a solvent extraction study of these complexes.

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A highly reliable optical sensor for oxygen-pressure measurements was developed. It was based on the phosphorescence quenching of platinum octaethylporphyrin incorporated in polymer films by oxygen. In this work, in order to overcome the shortcomings when the traditional spectrophotometer is used for oxygen sensing, the sensor behaviors were studied using a CCD-camera scanning technique. The Stern-Volmer plots of oxygen sensors showed improved linearity, compared with those of the traditional luminometer. The sensor was proved to have a good operational stability and <10% of the photobleaching was observed after storage for more than 1 year in the absence of light at room temperature.

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Beryllium(II) solvates [BeS_n(H₂O)_4-n]²⁺(n=0-4, S=N, N dimethylformamide (dmf) and 1, 1, 3, 3-tetramethylurea (tmu)) in acetonitrile have been characterized by ⁹Be NMR spectroscopy. The difference in steric effects of the bound dmf and tmu molecules on the structures of the solvates has been clarified by ⁹Be NMR chemical shifts. The stepwise formation constants, K_n=[[BeS_n(H₂O)_4-n]²⁺][H₂O][[BeS_n-1(H₂O)_5-n]²⁺]^-1[S]^-1(n=1-4), obtained from the ⁹Be NMR signal intensities for the tmu system drastically decrease between K₁ and K₂ and between K₃ and K₄, while those for the dmf system decrease statistically with an increase in n. Such a difference in the stability of the two systems is discussed in connection with the steric effects.

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The extraction of copper(II) with 2-(2-pyridylazo)-1-naphthol-4-sulfonic acid and tetrabutylammonium ion using the octane/1-octanol mixed solvent was carried out at 25°C. The formation and partition constants of ion associates formed between tetrabutylammonium ion and 2-(2-pyridylazo)-1-naphthol-4-sulfonate and/or its cuprate(II) anions were determined by an analysis of the extraction equilibria. The utility of the octane/ 1-octanol mixed solvent for ion association extraction systems can be demonstrated as a lower toxicity solvent than halogenated solvents, such as chloroform, 1, 2-dichloroethane etc.

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We immobilized double-stranded DNA on poly(N-isopropylacrylamide), which is temperature-sensitive and gives precipitates from an aqueous solution when heated over 31°C. Photochemical conjugation with a vinyl derivative of psoralen was demonstrated to make the DNA polymerizable with a vinyl monomer. The radical copolymerization with N-isopropylacrylamide gave the temperature-responsive conjugate. The conjugate was shown to capture ethidium, a D0NA-binding genotoxin, and precipitate with it when heated. About 95% of ethidium was separated from its highly diluted solution (3ppm).

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The major components of the fluid in a single parenchymatous cell of a citrus fruit were analyzed by various modes of high- performance capillary electrophoresis, including zone electrophoresis in the intact state (direct zone electrophoresis), zone electrophoresis as borate complexes and SDS micellar electrokinetic chromatography, and identified by successive introduction of the cell fluid and a solution containing authentic specimens of the major components, followed by comigration. The validity of identification by this co-migration technique is discussed based on experiments using cinnamyl alcohol and cinnamic acid as model compounds. On the other hand the volume of the cell fluid introduced to a capillary was estimated from the peak width of a neutral component, and the introduced amount of a particular component was determined from its peak area against the calibration curve. From these values of the introduced volume and amount, the concentration of this particular component could be easily estimated. This paper also gives an example of application of this method for determining the ascorbic acid concentration in single parenchymatous cells of various kinds of citrus fruits.

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Proteins labeled with the dye Rhodamine B isothiocyanate were separated by capillary zone electrophoresis using an untreated fused-silica capillary and buffer containing sodium dodecyl sulfate. The sodium dodecyl sulfate in the migration buffer eliminated or minimized the protein adsorption to the inner wall of the capillary and rendered the proteins negatively charged through hydrophobic interactions. Furthermore, an appropriate use of SDS during the labeling procedure was found to increase the solubility of the dyestuff, which in turn results in sensitive detection of the protein. The labeled proteins were separated successfully in an untreated capillary using a buffer containing sodium dodecyl sulfate and detected spectrophotometrically and fluorometrically with high sensitivity. Bovine serum albumin reacted with the dyestuff for 4, 12 and 24h at 20°C was detected by spectrophotometry at 556nm with approximately 2.5, 4.2 and 6.0 times, respectively, higher sensitivity than unlabeled protein. Fluorometric detection(λ_ex=563nm, λ_em= 577nm) further increased the detection sensitivity to approximately twice that of spectrophotometric detection at 556nm for the labeled protein.

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Capillary electrophoretic methods have been developed for the analysis of Monascus yellow pigments for food additives. Monascus yellow pigments were successfully separated by micellar electrokinetic chromatography (MEKC) with a 20mM sodium dodecyl sulfate (SDS) solution containing 50mM phosphate buffer, pH 7.0, and 20% acetonitorile or a 2.0% butyl acrylate/butyl methacrylate/methacrylic acid copolymer sodium salts (BBMA) solution containing 20mM ammonium formate buffer, pH 7.0, and 10% methanol. The xanthomonasin A was identified with the molecular mass measured by FABMS. Monascus yellow pigments were extracted from candies with solid phase extraction and analyzed by the developed technique.

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Horseradish peroxidase (HRP) was encapsultated in liposomes by an extrusion technique using polycarbonate filters with a pore size of 100, 400 and 1000nm. The vesicles formed by the extrusion technique (VETs) were characterized in terms of the size distribution, trapping efficiecy, and number of HRP molecules encapsulated in the inner compartment of the VETs. The number of HRP molecules encapsulated in the VET₁₀₀₀ was about 1200 HRP molecules per VET₁₀₀₀. The activity of HRP was found to remain throughout the encapsulation process by measuring the catalytic activity of HRP for a luminol chemiluminescence (CL). HRP was encapsulated inside the VET₁₀₀₀ for about one week at 4°C without any release through the lipid membranes.

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A method was developed for the quantification of 3, 4-dihydroxyphenylglycol (DHPG), 4-hydroxy-3-methoxymandelic acid (VMA), 4-hydroxy-3-methoxyphenylglycol (MHPG). The separation and determination of these compounds in biological samples were previously thought to be very difficult. In this work the separation has been well achieved by high-performance liquid chromatography on a reversed-phase column using three mobile phases with a step-wise gradient elution mode. The condition for coulometric detection has been developed for an effective determination of these compounds. In the analysis of the rat-brain tissue, DHPG, VMA and MHPG were separated and determined successfully. The average levels of DHPG, VMA, and MHPG in nine different rat-brain tissue samples were 11.8±0.57, 2.13±0.13 and 6.77±1.84ng/g wet brain, respectively. Simultaneously, their precursors DOPA, DA, NE, DOPAC, HVA, 3MT and NMN, and indolamine 5HT and its metabolite 5HIAA may also be determined by the same chromatographic run.

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An FIA system was developed to analyze urea by monitoring ammonium ions generated by enzymatic degradation with a tubular ion-selective electrode containing nonactin on polyvinyl chloride (PVC) membrane. As an urease source, 120mg of the leguminous canavalia brasiliensis were immobilized in an enzymatic reactor with glutaraldehyde. Ammonium ions are converted to ammonia by an alkaline solution, 1mol l^-1 NaOH, and permeates through a polytetrafluoroethylene membrane until the detector. The method can be used in an urea concentration range of 2.5×10^-4 to 2.5×10^-3mol 1^-1(25.0°C). Analysis of 25μl commercial samples of fertilizers, showed a relative error of 0.2% with a high selectivity to the species present.

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Based on the selective volatilization taking place between the matrix and the analyte in the graphite furnace, a new method for a direct ICP-AES determination of trace impurities in SiO₂ powder using electrothermal vaporization (ETV) as a slurry-sampling technique is described. A polytetrafluoroethylene (PTFE) emulsion is used as a fluorinating reagent to promote the vaporization of impurity elements from SiO₂ powder. The fluorinating vaporization and transportation behaviors, the matrix effects and the particle-size effects have been investigated systematically. When the sampling volumes are 10μl, the detection limits of Cu, Cr, Fe and Ti are 1.05, 1.58, 1.06 and 0.9μg l^-1, respectively, and the RSDs are in the range of 1.9-4.1%. The proposed method has been applied to analyze SiO₂ powder without any chemical pretreatment. The determined values are in good agreement with the results obtained by using acid decomposition-pneumatic nebulization ICP-AES.

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The organic phosphates analyzer, originally developed by us based on the anion-exchange separation on an Asahipak NH2P-50 column and the postcolumn phosphomolybdic acid reaction, was improved for the analysis of biological materials. The anion-exchange separation was optimized to resolve several model phosphates by using a LiCl linear gradient elution. An acetonitrile pretreatment method was devised for simple and effective deproteinization and the extraction of organic phosphates in rat heart muscle. The analyzer was successfully applied to the determination of organic phosphates in rat heart muscle.

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Cobalt(III) oxidation of diverse organic compounds was studied in a batch system. An aqueous solution of an organic compound was mixed with a cobalt(III) solution (ca. 0.04mol dm^-3), prepared through the electrolysis of a cobalt(II) solution in a strong acidic medium, with a volume ratio of 1:2. The oxidation of the organic compound was evaluated from the decrement in absorbance of the mixed solution at 610nm, the wavelength of absorption maximum of the cobalt(III) ions. The cobalt(III) ions were found to be strong enough to oxidatively decompose organic compounds at room temperature; the oxidation was rapid and almost complete in 10min. The chemical oxygen demand (COD) of sample solutions was calculated from the amount of cobalt(III) ions consumed for the oxidation. The obtained COD value for each sample was comparable to that determined by an official method based on permanganate oxidation. It is concluded that not only is the cobalt(III) oxidation practical for the treatment of organic compounds but it has possibilities as a novel method of COD determination, because it can be done rapidly in a simple operation with no requirement for heating.

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A coprecipitation method with hafnium hydroxide was studied for the determination of chromium(III) and chromium(VI) in water by graphite-furnace atomic absorption spectrometry. Both 0.04-1.6μg of chromium(III) and 0.04-1.6μg of Chromium(VI) in a 200cm³ water sample were quantitatively coprecipitated with hafnium hydroxide at pH 5.7; 0.04-1.6μg of chromium(III) alone was done at pH 11. Each of the precipitates obtained at pH 5.7 and 11 was dissolved in nitric acid; the solutions were then diluted to 10cm³ and subjected to determinations of the total amount of chromium(III) and chromium(VI) and the amount of chromium(III) alone, respectively. The detection limits were 0.02ng cm^-3 of chromium(III) and chromium(VI) in 200cm³ of the initial sample solutions. The thirty four matrix ions tested did not produce any serious interference effects in the chromium(III) determination. Although the presence of fluoride, phosphate, and sulfate tended to reduce the recovery of Chromium(VI), they could coexist up to amounts of 1mg, 1mg, and 50mg, respectively.

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The charring of samples and loss of mercury by a nitric-sulfuric acid mixture has been overcome by prior digestion with nitric acid, followed by the addition of sulfuric acid into the final solution. This approach provides optimum decomposition and analytical conditions for a reliable cold vapor atomic absorption spectrometric determination of mercury in biological and environmental materials. In all cases, the presence of sulfuric acid improved the sensitivity of the mercury response significantly. Furthermore, the prior- and post-addition of sulfuric acid gave similar sensitivity and mercury concentrations for all samples. The adequacy of the prior digestion with nitric acid and post-addition sulfuric acid for reliable mercury determination was successfully demonstrated for blood, bone, bovine liver, mushroom, lake sediment, peat and prawn samples.

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Selective determination of selenium(IV) and selenium(VI) in waste water by graphite furnace atomic absorption spectrometry (GFAAS) was developed. The method is based on the reductive coprecipitation of selenium(IV) by L-ascorbic acid or tin(II) chloride and of selenium(VI) by hydrazinium sulfate on a tellurium collector, followed by GFAAS. The ppb levels of selenium(IV) and selenium(VI) were quantitatively coprecipitated with 50-500μg amounts of tellurium collector in 100ml (1M HCl). The selective separation of selenium(IV) from selenium(VI) could be achieved in the presence of 0.2-4.0g of L-ascorbic acid or the optimized amount of tin(II) chloride (molar ratio [SnCl₂•2H₂O]/[Te(IV)]=50). The proposed methods were successfully applied to real waste-water samples and the standard reference material of river water (JA00032). The detection limit (3σ) was about 0.5ppb of selenium of the water sample.

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The conditions for a spectrophotometric determination of selenium with 1-naphthyloamine-7-sulfonic acid (Cleve′s acid) are presented. Se^IV forms a yellow complex with this ligand in sulfuric acid media with maximum absorbance at 350nm. The molar absorptivity is 8.9×10⁴l mol^-1 cm^-1. The calibration curve is linear up to 3.0μg of selenium with Sandell′s sensitivity being 0.0009μg cm^-2, i.e., the amount of Se in a column of unit cross-sectinal area which gives the absorbance of 0.001. The interference of various ions was studied. The method was applied for the determination of selenium in a vitamin supplement.

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The application of polyurethane foam for the preconcentration of Cypermethrin, Malathion and Parathion insecticides was examined by the static mode of extraction. The retention of the tested species from aqueous media with the polyether polyurethane foam suggests that the solvent extraction and the cation chelation mechanism might be operative. Quantitative retention and recovery of the tested insecticides by the foam column mode of separation were carried out and satisfactory recovery percentages (up to 99.10±3.12%) were obtained. The number and the height equivalent of the theoretical plate of the foam columns were found in the range of 165-170±4 and 1.85-1.93±0.26mm, respectively at 10cm³/min flow rate. Separation of the binary mixtures of Malathion-Cypermethrin and Parathion-Cypermethrin insecticides from the aqueous media was achieved successfully. The helical structure of the foam sorbents offfers rapid, versatile and effective separations and preconcentration of different compounds from fluid samples over conventional bulk-type granular sorbents.

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