分析化学におけるオニウム化合物の適用に関する研究(第5～6報)

Iodobismuthate ion and chlorobismuthate ion are formed to be determined amperometrically with triphenylselenonium chloride as precipitating reagent. As usual the precipitation reaction proceeds so slowly as to be given up titration, but according to the results of examination the 10 equivalents of iodide ion or 0.20.3N of hydrochloric acid is sufficient for making polarographically complete precipitation within 10 minutes after each portion of titrant is added. The average error of the amperometric titration is ± 1%.A solution of dodecyltrimethylammonium chloride, C12HR25(CH3)3NC1, at the concentration of 10-210-4M/l gives approximately-2. 2 volt (vs. mercury pool) of reduction potential and at that of 0. 1 M/l gives a wave similar to hydrogen wave having the maximum at around-1. 5 volt. The aqueous solution of this reagent is dissociated into [C12H25(CH3)3N]+ and Cl-; accordingly, it can be utilized for precipipitation reaction of metal ions, e. g. Hg (II), Bi (III), Cd (II), Sb (III), Sn (II), Sn (IV), Fe (III), Mn (II), Co (II), Ni (II) z.rd Zn (II), with the use of a suitable complexing agent, also, anions, e. g. Br-3, I-3, ClO-4, IO-4, VO3-4, CrO2-4, Cr2O2-7, MnO2-4, WO2-4 and MnO-4, are reacted to form the precipitate. Polarographic behaviors of dodecyltrimethylammonium chloride against metal ions, e. g. Co (II), Zn (II), Bi (III), Sb(III) and Hg (II), in the above metal ions and their amperometric titration are investigated.