Determination of pyridoxine hydrochloride in pharmaceutical preparations by calixarene based potentiometric sensor

A simple, rapid and sensitive sensor for the assay of pyridoxine hydrochloride has been developed. The method is based upon the use of calix-8-arene as a neutral carrier in the presence of phosphotungstic acid as an ion extruder and di isooctyl phthalate as plasticizer. The sensor was found to have a short response time of 20s to pyridoxine concentration. Perfectly Nernstian slope of 60.4+/-3.1 mV/decade of activity between pH 3.0 and 7.2 for the monovalent pyridoxine hydrochloride over a wide concentration range of 1 x 10(-1) M to 6.2 x 10(-6) M was observed. The detection limit observed was 1.6 x 10(-6) M. The selectivity coefficients of the developed sensor indicated excellent selectivity for pyridoxine hydrochloride over a number of species, which normally accompany pyridoxine in various pharmaceutical formulations. The mediator o-nitrophenyl octyl ether significantly increased the lifetime of the sensor. The results obtained for pharmaceutical sample analysis using this sensor were satisfactory with excellent recovery percentage comparable and sometimes even better than the ones obtained by other routine methods for the assay.