Makoto Kawane

Rapid determination of SO3 in Cements by an Anion Exchange Resin

The sulphate content of cements was determined by an anion exchange resin method. The sulphate ion was converted to chloride ion using Amberlite IRA-400. The chloride ion was titrated by the potentiometry. The results agreed with the results of the barium sulphate method, and were obtained in 2 or 3 hours.

Comparative Studies ou the Micro-Determination of Fluorine

Colorimetric determination of a sample solution of NaF containing less than 10p.p.m. F- were made by use of a) ferric thiocyanate method, b) ferric salicylate method, c) thorium alizarin method, d) zirconium alizarin method, and e) aluminum hematoxylin method in the presence or absence of the disturbing ions. Within the range of showing linear transmittancy coefficient against the concentration, statistical interpretation of the result by Youden method was applied and found that the b) method was disturbed by CO--3, and that of the a) and c) methods by SO--4, The b) method was the most suitable for determination of less than 10p.p.m. F-, since this method required less time, reagents used are stable and the method has good accuracy and high sensitivity. Also, c) or d) method was suitable for determination of less than 5p.p.m. F-.

Determination of moisture in papers by Karl Fischer method

The sample of papers containing 20-30mg. of water was weighed into a 300ml. flask containing 30ml, dry methanol. After agitation for 30min. at room temperature, the moisture was titrated with Karl Fischer reagent.Based on data obtained, the moisture in papers appears to be completely extracted with methanol in 30min. agitation. Comparative data were obtained employing the weight loss method at 102°C.Results obtained on several papers are summarized in Table 1. From these data it is seen that the moisture values by Karl Fischer method are somewhat higher than those by weight loss method.