Selectivity for phosphate and citrate with benzyltin‐based polymer membrane electrodes

Abstract

Response properties are reported for membrane electrodes prepared by incorporating bis(p‐fluorobenzyl)tin dichloride, bis(p‐chlorobenzyl)tin dichloride, and tris(p‐chlorobenzyl)tin chloride into plasticized poly(vinyl chloride) membranes. These electrodes respond selectively to dibasic phosphate and tribasic citrate. The magnitude of response and the degree of selectivity are affected by the method of pretreating the membrane. The highest level of selectivity is obtained for tribasic citrate from electrodes based on bis(p‐fluorobenzyl)tin dichloride after conditioning with citrate. This electrode possesses a limit of detection for citrate of 0.4 μM at pH 7.0 with response times ranging from 2 to 5 minutes. Selectivity for citrate is demonstrated over phosphate, thiocyanate, iodide, bromide, nitrate, acetate, lactate, pyruvate, ascorbate, and chloride. Copyright © 1993 VCH Publishers, Inc.