Effect of temperature on the electrical resistance and voltage departures (errors) of glass electrodes, and upon the hygroscopicity of glass

Abstract

.The effect of temperature upon t he electrical resbtance and pH respo nse h as bee n studied on elec trodes prepared from t hree types of g lasses: P yrex 7740, comme rcia l softglass .tubing, and Co rnin g 015 ; glasses of low, in termediate, and hi gh hygroscop icity, respectively. The r esults show t ha t e lectrica l resistance is not the dete rminant in most cases of vol tage departure from t he t heo retical, and in t he inherent fai lure of many glasses to act a s satisfa ctory indicators of hyd rogen-ion activity of aq ueo us solu t ions. FO I' examp le, t he electrod es prepared fr om Pyrex glass gave no signifi can t pH res ponse e ve n wh e n t he resistance was as low as 12 megohm s. The res ul ts of e lectrodes from glasses of in te rm edia te h ygroscopicity gave a pse udo-co rresponde nce of pH res ponse with resistance whe reas electrodes of Cornin g 015 gave vo ltage de part ures that co uld in no wa y be a tt ribu ted to the electri cal resistance of t he e lec trode ..

Potentiometric Titrations

“…Hubbard (63) has studied the temperature effect on electrical resistance and voltage errors of glass electrodes. Glass electrode failures wrere attributed to low' hygroscopicity of the glass, excessive wall thickness, poor chemical durability, high electrolyte concentration, and inhibiting films.…”