N-(2-アミノエチル)-N-(2-ヒドロキシエチル)ジチオカルバミン酸を用いる銅(II)の吸光光度定量
1978 年 27 巻 1 号 p. 58-59
詳細
1978 年 27 巻 1 号 p. 58-59
The N-(2-aminoethyl)-N-(2-hydroxyethyl) dithiocarbamic acid (Hahdtc) reacts with copper(II) and forms a water-soluble complex having an absorption maximum at 432 nm. The absorbance of the complex at the wave-length is maximum and constant when the pH of the sample is in the range of 3.5 and 7.6, moreover. at pH 4.5, it does not change for 45 min. Beer's law holds for (3.21102.6)μg of copper (II) in the sample of 25-ml volume with the molar absorption coefficient ε432= (1.29 ±0.02) × 104 cm-1 mol-1 1, being Sandell's sensitivity (4.9±0.6) × 10-3μg cm-2. The recommended procedure is as follows. To (3.21102.6)μg of copper in a 25-ml volumetric flask are added 5 ml of 2 mM Hahdtc solution and 5 ml of acetate buffer solution (pH 4.5). The mixture is filled up to 25 ml with water. The absorbance measurement is carried out at 432 nm against water within 30 min after mixing. Less than 10 mg Al(III), Ca(II), Cd(II), Mg(II), Mn(II) and Zn(II), less than 1 mg Pb(II) and less than 0.5 mg Cr (III) do not interfere. Interference by 1 mg of Bi (III), Co(II) and Ni(II) is masked by the addition of Na2H2edta. Less than 10 mg Fe(III) is masked by reduction with ascorbic acid. Less than 0.2 mg Hg(II) does not interfere, but when Na2H2edta coexists, it interferes seriously.
