Patent ID: 7883898
Filing Date: 2011-02-08
Classification: G01N,Y10T

Abstract:
1. A method for measuring pH of a low alkalinity sample solution, comprising the steps of: providing a pH sensor array having a plurality of pH indicator films, each said pH indicator film having a different indicator-concentration; applying said sensor array to a series of pH standard solutions having fixed and known pH and alkalinity values; simultaneously measuring a pH response for each pH indicator film of said sensor array; generating a calibration equation for each pH indicator film that provides the apparent pH as a function of said pH response, said calibration equations are generated using said pH responses for each pH indicator film from said series of pH standard solutions; applying said sensor array to a low alkalinity sample solution having an unknown pH and an alkalinity of less than 100 ppm; calculating preliminary pH values for each film from each corresponding calibration equation and pH response using the equation: where: calculating the actual pH value for the low alkalinity sample solution using the extrapolation equation: where: