I thought the idea of fentanyl diversion and Cdex sounded familiar. It took the staff awhile but after some searching found references to development of a battery operated fentanyl detector. Contacts with former employee(s) confirmed that there was indeed such a device developed by none other than the former engineer of Cdex, Ryles.
ValiMed(TM) LVM (a mobile, battery operated fentanyl detector)
Capt-spam also made several references to it. It was a "miniature version of the valimed that was battery operated and detected only one drug , fentanyl" (SIC).