A method of determining a component of a medium comprises illuminating the medium to excite a marker associated with the component. Detected photoluminescent emission from the marker in response to the excitation is compared with one or more emission profiles. The component is identified based on a match between the detected photoluminescent emission and at least one of the emission profiles.
|Patent number||US 7,256,398 B2|
|Publication status||Published - 14 Aug 2007|
Ross, G. A., Johnson, G. I., Clark, B., Forrest, S. J., Cegalis, J., Greaves, W. J., & Maney, C. Q. (2007). Security markers for determining composition of a medium. (Patent No. US 7,256,398 B2). USPTO (United States Patent and Trademark Office).