Patent ID: 11965452
Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
Field: Measurement (Instruments)
Classification: CPC F  G | IPC F  G

Claim 11:
12. A method for detecting contaminants in a vehicle coolant system during service, the method comprising:
contacting a chromophore impregnated strip and a heat transfer fluid sample, the chromophore impregnated strip comprising a first complexing agent and a second complexing agent distinct from the first complexing agent, the first complexing agent being selected to form a complex with a first contaminant that causes a first color change in the chromophore impregnated strip at a first location indicating the presence of the first contaminant in the heat transfer fluid sample, and the second complexing agent being selected to form a complex with a second contaminant that causes a second color change in the chromophore impregnated strip at a second location indicating the presence of the second contaminant in the heat transfer fluid sample, and the first and second contaminants comprising one or more compounds comprising elements independently selected from the group consisting of: aluminum, copper, fluorine, and combinations thereof.