Patent ID: 7049831

Claim:
A fluid property quality control method, comprising the steps of: a) obtaining a set of calibration fluids representative of a manufacturing process; b) performing impedance measurements on each of the calibration fluids to obtain first impedance spectroscopy (IS) data, wherein the first IS data include data for at least three frequencies; c) analyzing the first IS data providing first IS signatures indicative of properties for each of the calibration fluids; d) performing impedance measurements on a test fluid providing second IS data, wherein the second IS data include data for at least three frequencies; e) analyzing the second IS data providing second IS signatures indicative of properties of the test fluid; f) comparing the first IS signatures and the second IS signatures providing quality control information relating to the properties of the test fluid; and g) modifying the manufacturing process responsive to the quality control information; wherein the step of analyzing the first IS data and the step of analyzing the second IS data include equivalent circuit modeling, and the first IS signatures and the second IS signatures include at least one of the following: a bulk fluid resistance R fluid , a bulk fluid capacitance C fluid , a bulk fluid time constant τ fluid , an interface capacitance C dl , a charge transfer resistance R ct , an interface time constant τ i , an interface resistance R i , a Constant Phase Element Q i , a Constant Phase Element exponent n, a film time constant τ film , a film resistance R film , and a film capacitance C film .