According to the US Bureau of Justice, in the years 2007–09 more than half of state prisoners and nearly two-thirds of sentenced prison inmates met formal criteria for drug dependence or abuse. But how do the drugs get into prisons? They enter illegally inside of body cavities, baby diapers, bibles, and of course the mail. Once stationery is treated with a concentrated solution of heroin, MDMA, LSD, or fentanyl, small portions of a letter can be easily distributed among inmates. Narcotics in prison mail is such an issue that millions of dollars are being spent to re-work the system. Digitizing each piece of mail is one solution, but it is an imperfect one. It is time and personnel intensive, does not protect digitizers from harmful mail content, and it could potentially violate inmates’ rights. It is truly a complicated issue made even more complex by fentanyl. Mere exposure to trace amounts of fentanyl can be toxic for anyone handling laced mail, and death by fentanyl overdose is an issue on both sides of the bars. An ideal solution therefore would be a detection system that is quick, accurate, and efficient, and can test for the presence of drugs on paper at the point of receipt. Metrohm Raman offers excellent trace-detection solutions with both MISA and MIRA XTR DS systems, which can be used for instant onsite detection of opioids, cocaine, MDMA, and fentanyl. This Application Note describes trace detection of fentanyl on paper.

To demonstrate SERS detection of illicit drug-laced mail, this experiment begins with notebook paper cut into 0.635 cm (0.25 inch) squares. A stock solution of 0.1 mg/mL fentanyl in methanol was prepared and deposited onto these squares in the following volumes: 1 μL, 5 μL, 10 μL, 20 μL, and 50 μL to yield 0.1 μg, 0.5 μg, 1 μg, 2 μg, and 5 μg of fentanyl per 0.635 cm². Each square was dried and placed into a glass vial with 500 μL of silver colloid. This vial was capped, shaken, and rested for five minutes to enhance extraction. Saline solution (100 μL of 0.9%) was added and the vial was agitated gently to mix. After one minute, this mixture was measured with the ID Kit OP on MIRA XTR DS, with results shown in Figure 2.

SERS provides instant on-site identification of fentanyl in laced mail in four simple steps, as illustrated in the images above:

1. Remove a small sample of the suspect paper
2. Extract active compounds by shaking the paper sample in a vial with colloids.
3. Add saline solution to the vial.
4. Acquire data with ID Kit OP on MIRA or MISA

The results are unambiguous identification of fentanyl (Figure 3).