Electrochemical Behavior of Silicotungstic Acid Modified Ion-Sensitive Fieldistor (ISFET) Sensor Prepared with Sol-gel Technique

The association complex of a “Keggin” heteropolyacid,silicotungstic acid,with atropine was admixed with sol-gel,which was then applied to the surface of grid of ISFET,and a sensor having sensitive response toward atropine was prepared.A thorough study on its electrochemical behavior was performed,showing that not only the characteristics of ISFET was maintained,but also stable and sensitive Nernst response toward atropine with a slope of 59.0 mV/pc over the concentration range 1.0×10-3-5.0×10-6mol·L-1 at pH 3.0-8.0 was obtained.Detection limit of this method was found to be 1.0×10-6mol·L-1.In its application to the analysis of atropine injection,results obtained were in consistency with results found by pharmacopoeia method.