元素硫黃의 polalograph 擧動에 關韓 硏究

Abstract

微量의 元素硫黃 分析에 polarograph法을 適用함에 있어 polarograph 擧動을 支持電解溶液의 組成, pH 등의 電解條件에서 檢討함과 同時에 微量 定量 分析法을 檢討하였다. 水銀滴下電極에서 硫黃의 還元은 2電子 反應으로 直流, 또는 交流 polarogram은 pH 範圍 4~6의 酸性側 支持電解液中에서 가장 좋은 一段波의 還元波를 形成한다. 이들 還元波의 半波電位는 支持電解液의 pH에 依存하게 되며, 交流 polarography에서 얻어지는 peak電位와 元素硫黃의 濃度의 對數와의 關係曲線은 30mV의 기울기로서 直線性을 나타내어 Stackelberg의 理論과 一致한다. 元素硫黃의 定重分析은 直流 polarograph에서는 飽和甘汞電極을 對極으로 하여 支持電解液 pyridine-c-HCl-methanel(pH=4.6)中에서 , 交流 polarograph法에서는 水銀池를 對極으로 하여 支持電解液 methnol-benzene-pyridine-c-HCl(pH= 4.0) 中에서 가장 좋은 檢量線을 얻을 수 있다. 特히 元素硫黃의 含量이 1ppm에서 20ppm까지의 微量分析에 있어서는 交流 polarograph法에 依한 方法이 가장 높은 感度로 測定된다.;The analysIs of elemental sulfur by polarography already has been reporbed in the literature. Only a discussion of the more important factors influencing the analysis is presented here. (l) The effects of pH on the reduction of elemental sulfur are pronounced, and the use of buffered sdIutions for the analysis of elemental sulfur are in necessary. The author found that a pH of 4-6 has been obtained to be reproducible polarograms by use of D. C. polarography. However, in alkali solvents the plateau of the polarograms of elemental sulfur has a pronounced dip if the concentration of sulfur is as much as 30 ppm. (2) A. C, polarographic method shows a very high sensitivity in the case of sulfur reduction, so that the very low concentraction of sulfur can easily be determined (about 1 ppm). (3) The characteristics of sulfur wave can be formulated accordIng to Stackelberg-Hauck-Hans equation. It was found that the curve of the peak potential of alemental sulfur in A. C. polarography versus logarithm of sulfur concentration was obtained to be straight line with the slope of 29.6 millivolts. This result were well agreed with theoretical consideration. (4) It was assumed that this polarographical methods were applicable to micro-analysis of alemental sulfur in crude oil and its petrochemical products, precipitated sulfur, sulfur ointments with accuracy and rapidity.