Metabolites of drugs of abuse can be detected in fingerprints using mass spectrometry technology, according to a small study published May 1 in The Analyst. Both fingerprints and oral fluid were analyzed from five patients attending a drug and alcohol treatment service. Oral fluids were tested using chromatography mass spectrometry, while fingerprints were analyzed using Desorption Electrospray Ionization (DESI) with Ion Mobility Tandem Mass Spectrometry Matrix Assisted Laser Desorption Ionization (MALDI-IMS-MS/MS) and Secondary Ion Mass Spectrometry (SIMS).“Natural” fingerprints were placed onto clean glass slides. The researchers found that both DESI and MALDI were able to detect the cocaine metabolites benzoylecgonine (BZE) and methylecgonine (EME) in latent fingerprints. There was “good” correlation between fingerprint analysis and oral fluid testing, but the authors say that development of a quantitative test with a standard cut-off level is an important next step. SIMS’ sensitivity was “insufficient.” “The ability to detect excreted substances in latent fingerprints proves that surface MS techniques could provide the drug testing industry with an exciting new and complementary tool, potentially allowing differentiation between drug consumption and contact solely based on the presence of metabolites in the residue,” writes lead author Melanie Bailey, Ph.D., from the University of Surrey (United Kingdom). […]
Metabolites of drugs of abuse can be detected in fingerprints using mass spectrometry technology, according to a small study published May 1 in The Analyst.
Both fingerprints and oral fluid were analyzed from five patients attending a drug and alcohol treatment service. Oral fluids were tested using chromatography mass spectrometry, while fingerprints were analyzed using Desorption Electrospray Ionization (DESI) with Ion Mobility Tandem Mass Spectrometry Matrix Assisted Laser Desorption Ionization (MALDI-IMS-MS/MS) and Secondary Ion Mass Spectrometry (SIMS).“Natural” fingerprints were placed onto clean glass slides.
The researchers found that both DESI and MALDI were able to detect the cocaine metabolites benzoylecgonine (BZE) and methylecgonine (EME) in latent fingerprints. There was “good” correlation between fingerprint analysis and oral fluid testing, but the authors say that development of a quantitative test with a standard cut-off level is an important next step. SIMS’ sensitivity was “insufficient.”
“The ability to detect excreted substances in latent fingerprints proves that surface MS techniques could provide the drug testing industry with an exciting new and complementary tool, potentially allowing differentiation between drug consumption and contact solely based on the presence of metabolites in the residue,” writes lead author Melanie Bailey, Ph.D., from the University of Surrey (United Kingdom).
Fingerprints afford advantages over other noninvasive samples such as saliva, hair, and sweat including ease of sampling and transport and that the identity of the donor is captured within the sample, making the test impossible to falsify. MS-based analysis offers “a high level of selectivity,” while only consuming a small portion of the sample fingerprint, allowing repeat analyses of a single sample. However, the authors caution that a sampling regime needs to be established to address the lack of spatial uniformity among fingerprints. Additionally, a quantitative procedure is needed, as there is currently no accepted method for determining how much material was deposited in the fingerprint sample, as opposed to blood, urine or oral fluid, where the sample volume is known.
“Companies are already working on miniaturized mass spectrometers, and in the future portable fingerprint drugs tests could be deployed ,” said Bailey in a statement.
Takeaway: With further validation and refinement of sampling procedures, analysis of metabolites of drugs of abuse through fingerprint residues may be possible in the field.
