非イオン性界面活性剤の電位差及び定電圧分極電流滴定

概要

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The well known Schonfeldt method is a very useful volumetric method for the determination of nonionic sufactants. However, this method is not rapid because the filtration of the precipitate is required. In the prsent work, the direct titration of a nonionic surfactant with potassium hexacyanoferrate(II) was investigated. It was found that a sharp end-point in the potentiometric titration with a platnum indicator electrode was obtained in the presence of a small amount of potassium hexacyanoferrate(III) as a reversible redox system. Furthermore, in a biamperometric method in which two plathume electrodes of the same size polarized by a DC potential difference of 50mV, a good result was observed in the presence of more than 5 cm^3 of 5 (w/v)% potassium hexacyanoferrate (III). The established procedure is as follows. To (2.5〜15.O)cm^3 of 2(w/v)% Triton X-100 (iso-octyl phenoxylpolyethoxy ethanol) solution, are added 20 cm^3 of 6N HCl and 15g of NaCl. After the addition of two drops of 1 (w/v)% potassium hexacyanoferrate (III) solution in the potentiometric method, or 5 dm^3 of 5 (wlv)% potassium hexacyanoferrate(III) solution in the biamperometric method, the solution is diluted to ca.110 cm^3 and titrated directly with 0.05mol dm^<-2> potassium hexacyanoferrate(II) solution. The amount of K_4[Fe(CN)_6] required in the titration is proportional to that of Triton X-l00 present in the solution.
社団法人日本分析化学会の論文
1975-09-10