Evaluation of Four Fingerprint Development Methods for Touch Chemistry Using Matrix-Assisted Laser Desorption...

Area of Science:

• Forensic Science
• Analytical Chemistry
• Mass Spectrometry

Background:

• Latent fingerprints, or "touch chemistry," offer valuable forensic intelligence.
• Developing effective methods for chemical analysis of fingerprints is crucial for investigations.
• Existing identification techniques need to be compatible with new analytical approaches.

Purpose of the Study:

• To compare four preparation techniques for MALDI/TOF mass spectrometry.
• To evaluate the effectiveness of these techniques in analyzing chemical residues in latent fingerprints.
• To determine the potential for gathering intelligence from fingerprint "touch chemistry."

Main Methods:

• Ten volunteers deposited fingerprints containing drugs and explosives onto microscope slides.
• Four preparation methods were tested: fingerprint powder, MALDI matrix, fingerprint powder with lifting, and cyanoacrylate fuming with fingerprint powder.
• Qualitative identification was performed using ion images and mass spectra from MALDI/TOF mass spectrometry.

Main Results:

• Methods using fingerprint powder (A) and MALDI matrix (B) achieved the highest average detection rates at 88%.
• Methods involving fingerprint powder with lifting (C) and cyanoacrylate fuming (D) showed limited success with detection rates of 52% and 18%, respectively.
• Imaging coupled with mass spectral data was vital for detecting analytes in fingerprints.

Conclusions:

• Fingerprint powder and MALDI matrix are effective preparation techniques for chemical analysis of latent fingerprints using MALDI/TOF mass spectrometry.
• Touch chemistry analysis holds significant potential for gathering forensic intelligence.
• Further development of touch chemistry applications could enhance investigative capabilities.