Chitosan Based Heterogeneous Membrane Sensor for pH – A Prototype

摘要

A heterogeneous membrane pH sensor based on chitosan, polyvinyl chloride (PVC) and a suitableplasticizer was developed. The best overall performance was shown by a membrane with compositionratio of chitosan (ionophore) : PVC (binder) : 2-nitrophenyl octylether (2-NPOE) (plasticizer) at 20 :30 : 30 (% w/W) respectively. The potentiometric responses was linear within pH 2 to 9, limit of-1 o detection at pH 9.5, slope 56 mV decade at 25 1 C and response time of 20 5 s. A life time ofmore than 3 months was obtained. The sensor established good selectivity and reproducibility towardshydrogen ion in the presence of other cations. Results were in good agreement with a commercial pHelectrode for pH measurement in fruit juice samples.