誘導結合型プラズマ質量分析法（ICP-MS），誘導結合型プラズマ発光分析法（ICP-AES）を利用した下水汚泥中多元素定量法を開発した．試料の溶液化はマイクロ波酸分解法又はアルカリ融解法で行い，元素測定にはICP-MS及びICP-AESを用いた．分析値の評価には，Institute for Reference Materials and Measurements（ヨーロッパ共同体標準物質計測研究所，IRMM）より頒布されている下水汚泥標準物質（BCR-144R）を使用した．アルカリ融解法では，Zn，Cu，Pb，Ni，Co，Cdで保証値より定量値が低くなった．この濃度低下はZn，Pb，CoとCdでは揮発，Cu及びNiではPtるつぼへの合金形成が主な要因であることが分かった．また，Nb，Ta，Hfの溶解にはマイクロ波酸分解法及びアルカリ融解法双方において溶解液へのフッ化水素酸の添加が必要であった．そこで，徳島市で採取した下水汚泥実試料をマイクロ波酸分解/ICP-MS，ICP-AES法により分析した結果，計44元素の定量が可能であった．
In an investigation on the behavior of a cadmium ion-selective electrode in methanol–water and ethanol–water mixtures, potential measurements were carried out with a digital pH/mV meter, a cadmium ion-selective indicator electrode and a silver–silver chloride reference electrode. The calibration curves, slopes of the response, response times, effects of temperature, relation between the potential and the pH-meter reading and selectivity of the electrode were discussed. The response of cadmium ions (electromotive force) was linear between 10−7–10−2 mol dm−3 in water. However, the linear range became narrower with an increase in the alcohol content. The slopes in alcohol–water mixtures (27–33 mV/decade in methanol–water mixtures, 21–29 mV/decade in ethanol–water mixtures) were nearly equal to the Nernstian slope (29.6 mV/decade). The response times of the cadmium ion-selective electrode in 99 v/v% methanol and in 99 v/v% ethanol were somewhat long, but were still within 5 min for all solutions consisting of...
A micro enzyme-sensor, based on galactose oxidase (EC 1.2.3.9) and a tris(2,2′-bipyridine) complex of osmium(II/III) as a redox mediator ([Os(bpy)3]2+/3+), fabricated on a carbon electrode (25 μm diameter), was developed for measuring galactose. To obtain the carbon electrode, a platinum-disk electrode (25 μm diameter) was etched in hot aqua regia to create a cavity (depth of ca. 3—5 μm) at its tip. A porous carbon material was prepared from 90% acetylene black and 10% Teflon emulsion as a binder, and then packed into the cavity of the platinum-disk electrode’s tip. The carbon electrode was immersed in the osmium complex with 0.1 mol dm−3 LiClO4 in order to adsorb it in the carbon pores, which was monitored based on an increase in the anodic peak current and the cathodic peak current based on the osmium complex redox potential by the cyclic voltammogram. The tip of the carbon electrode was dipped overnight in a buffer solution of pH 7.00 containing galactose oxidase so as to immobilize it on this surface ...
Ionic liquids are expected to replace conventional organic solvents in organic synthesis, solvent extraction and electrochemistry due to their unique characters such as low volatility, high stability and so on. In this work, N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide was used as an alternative solvent to extract heavy metal ions. As the extracting conditions, the additional effect of 8-hydroxyquinoline (8-HQ) as metal chelating agent into ionic liquids, shaking time and volume ratio were investigated. As extraction efficiency depended on 8-HQ concentration significantly, in order to extract high concentrated metal ions the solubility of 8-HQ into ionic liquid was tested. N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide had good solubility of 8-HQ. Consequently, 5 μmol of copper, zinc, cadmium and manganese could be completely recovered with 100 μl of ionic liquid.
A porous micro-electrode with immobilized poly(methacryroyl alanine) (PMA) was developed for measuring copper(II) ion ( Cu 2+ ) and cadmium(II) ion ( Cd 2+ ). A porous carbon material was packed into the tip of the platinum micro-electrode with a cavity at the top. The porous micro-electrode was dipped in the coating dimethyl sulfoxide solution with PMA and di-2-ethylhexyl phthalate and dried overnight at room temperature. The immobilized PMA on the porous micro-electrode had predominantly a keto form in the buffer solution. In the enol form a metal complex can be formed under the simultaneous liberation of a proton. Calibration curves for measurements of Cu 2+ and Cd 2+ , the effects of preconcentration condition, scan rate, pH, and temperature, and lifetime of the PMA modified micro-electrode were examined. Under optimal conditions, the responses of sensor were linear in the concentration range 0.0001~1 mmol 1 -1 for Cu 2+ and 0.01~1 mmol 1 -1 for Cd 2+ . Analytical values determined with the modified electrode were constant for at least 3 month.
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