Analytical Sciences

Abstract − Analytical Sciences, 17(10), 1175 (2001).

Highly Selective Iodide-sensing Silicone Ladder Polymer Membranes Containing a Porphyrin and a Quaternary Ammonium Salt
Yutaka TSUJIMURA, Masataka YAMANE, and Shin-ichi WAKIDA
National Institute of Advanced Industrial Science and Technology Kansai, 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan
It has been demonstrated that a glass-like silicone ladder-type polymer permits one to homogeneously incorporate high amounts of ionophores into the covalently-bonded double chain structure. Furthermore, by making use of this feature, we have successfully fabricated an iodide ion-sensitive field-effect transistor based on two kinds of ionophores and silicone ladder polymer matrix. As ionophores, 5,10,15,20-tetraphenyl-21H,23H-porphyrin and dimethyloctadecyl-3-trimethoxylsilylpropylammonium chloride were homogeneously incorporated into the matrix. The ion-sensitive field-effect transistor showed a linear potential response ranging in the I- concentration between 1.0 x 10-5 and 1.0 x 10-1 M. The selectivity coefficients for I- towards interferences of ClO4- and NO3- were estimated to be KpotI-,ClO4- = 6.2 x 10-4 and KpotI-,NO3- = 4.9 x 10-4. The matrix has proved to be so stable that the selectivity coefficients have not been altered over six months.