Patent ID: 7598085
Filing Date: 2009-10-06
Classification: F01P,G01N

Abstract:
1. A method for determining the presence or absence of a corrosion-inhibitory level of carboxylate anion in used engine coolant which comprises: a. obtaining a known quantity of the engine coolant as a representative sample thereof, the sample containing a level of carboxylate anion to be determined; b. adding a fixed quantity of an aluminum containing color indicator to the sample, wherein the color of the aluminum color indicator is different from the original color of the sample, thereby changing the color of the sample to substantially the color of the aluminum color indicator, wherein at least a portion of the aluminum color indicator complexes with at least a portion of the carboxylate anion to form a colored insoluble aluminum-carboxylate complex, wherein the colored insoluble aluminum-carboxylate complex precipitates, and wherein the color of the sample remains substantially the color of the aluminum color indicator when the level of carboxylate anion therein is below an effective corrosion-inhibitory amount and wherein the color of the sample returns substantially to the original color of the sample when the level of carboxylate anion is at an effective corrosion-inhibitory amount; and c. observing the color of the sample.