Sodium titanate was impregnated onto a 6-nylon fiber by means of radiation-induced graft polymerization of dimethylaminopropyl acrylamide （DMAPAA） and subsequent chemical modifications. Peroxotitanium complex anions were bound to the DMAPAA-grafted fiber, followed by a reaction with sodium hydroxide to form sodium titanate as precipitate on the fiber. A quantitative elution of sodium titanate impregnated onto the fiber with 1 M nitric acid revealed that the molar ratio of Na to Ti was 0.76, which was almost consistent with that of sodium titanate （Na4Ti5O12） produced in a homogeneous system. During the immersion of sodium titanate-impregnated fiber in a mixture of 0.5 M NaCl and 0.05 M SrCl2, a molar ion-exchange ratio of Sr with Na was determined as being 0.55 by a quantitative elution of Sr-containing precipitate on the fiber.
Cation-exchange membranes （CEMs） were prepared from polysulfone （PSF）-based graft copolymers with graft chains of poly（sodium styrene sulfonate）. The graft-copolymers were synthesized by grafting ethyl p-styrenesulfonate （EtSS） on macro-initiators of chloromethylated PSF with different chloromethyl （CM） groups, thus changing the EtSS content in the polymers by using atom transfer radical polymerization. The transport number of the CEM （CM content ＝ 8.4 mol ％, and EtSS ratio ＝ 46 wt.％） was 0.98, almost the same as that of a commercial CEM, Neosepta® CMX （ASTOM Corp., Japan）, 0.98. The membrane resistance of the PSF-based CEM was 2.3 Ω・cm2, and lower than that of CMX, 3.0 Ω・cm2.
A flow injection analysis （FIA） method is presented as a means of reducing the workload required to determine hexacyanoferrate （II） （ferrocyanide） in salt. This method is based on the detection reaction of adsorbed ferrocyanide to Fe （III） complex with 1,10-phenanthroline. Automated analytical systems have been developed in which the sample injection and change of the flow path are automated. In addition, we investigated the appropriate concentration and pH of the sample solution, as well as the influence of the ferroin concentration. As a result, the FIA method described in this paper successfully determined the ferrocyanide ion in commercial salt.