Application Examples

Drugs and Narcotics

P-SERS™ substrates offer excellent performance for the detection of a wide variety of drugs and narcotics. This has a few key implications:

  • Fluorescent street samples, such as heroin, can be easily identified using your existing Raman instrumentation
  • Mixtures of drugs at dissimilar concentrations can be identified, for example heroin cut with fentanyl (fentanyl is ~20 times more potent than Heroin, so a small amount is often added to Heroin to boost potency, causing overdose and death for unsuspecting users)
  • Trace narcotic residues can be easily identified, through a simple P-SERS™ swab of an empty bag, table, etc. followed by Raman measurement

Measurements of seized street drugs: 

P-SERS SERS measurement of Black  Tar Heroin, compared to a Raman Heroin measurement

SERS of a seized street sample of Heroin cut with Fentanyl

P-SERS™ swab of surface containing 5 µg of cocaine

Identification of Black Tar Heroin* using P-SERS™ (without SERS the main heroin peaks cannot be detected due to fluorescence)

Detection of heroin cut with fentanyl (seized street sample*)

Detection of a trace narcotic residue (5 µg of Cocaine applied to a surface before swabbing with a P-SERS™ swab)

Measurements of drug standards:

Cocaine SERS spectrum on P-SERS 2.0 with 1% HCl

Heroin SERS spectrum on Silver P-SERS

Methamphetamine SERS spectrum on P-SERS 2.0

Droplet of 1 mg/mL cocaine applied to a P-SERS 2.0 substrate with 1% HCl

Droplet of 1 mg/mL heroin applied to a Silver P-SERS substrate

Droplet of 1 mg/mL methamphetamine applied to a P-SERS 2.0 substrate

*We’d like to acknowledge and thank the Maryland State Police for giving us the opportunity to perform these measurements.

Authentication and Anti-Counterfeiting

P-SERS™ technology enables a unique approach to covert “in-product tagging”, in which minimal (ppb level) amounts of molecular taggants can be added to a product, forming an “invisible barcode”. This invisible barcode can then be detected at any point later in the supply chain using a quick P-SERS™ dip or swab and measuring with a handheld spectrometer. FDA approved taggants are available.

Biologicals

P-SERS™ has the capability detect the Raman signature of various bacteria and proteins. Here, we show an example in which bacillus stearothermophilus in media has been applied to a P-SERS™ substrate and immediately measured.

 

P-SERS™ SERS detection of the bacteria Bacillus stearothermophilus

Food Safety

P-SERS™ can be used to detect trace contaminants in food, from pesticide and insecticide residues to adulterants such as melamine.

P-SERS SERS spectrum from a 300 ng Thiram surface swab
P-SERS™ SERS detection of 10 ppm Melamine in Infant Formula

Here 300 ng of the fungicide Thiram was applied to a surface and then allowed to dry. Then a P-SERS™ swab wetted with acetone was used to wipe across the surface before measurement.

Here we show the SERS detection of 10 ppm melamine in infant formula, after applying the infant formula to a custom P-SERS™ strip and performing a brief on-strip separation to eliminate the blocking effects of the interferents in the formula.

Explosives

Detection of 1 µg TNT applied to a P-SERS™ substrate.

P-SERS SERS measurement of TNT