Untargeted Metabolomics for Forensic Body Fluid Identification-A Pilot Study.

Area of Science:

• Forensic Science
• Analytical Chemistry
• Metabolomics

Background:

• Current body fluid identification (BFI) methods lack sensitivity and specificity.
• Metabolites, as specific biomarkers, offer potential for improved BFI.
• Advanced mass spectrometry techniques are underexplored for forensic BFI.

Purpose of the Study:

• To investigate body fluid/tissue specific metabolite markers using high-resolution mass spectrometry.
• To develop a novel analytical approach for identifying the origin of biological traces.
• To assess the potential of metabolomics in forensic casework.

Main Methods:

• Employed untargeted liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).
• Analyzed nine biological fluids/tissues: feces, fingerprick blood, menstrual blood, saliva, semen, skin, urine, vaginal fluid, and venous blood.
• Utilized sparse partial least-squares discriminant analysis (sPLS-DA) and generalized local learning (GLL) for feature selection.

Main Results:

• Identified key metabolite features responsible for body fluid/tissue-specific clustering.
• Selected features directly associated with specific body fluids/tissues.
• Presented nine predictive metabolite features, one for each sample type.

Conclusions:

• The developed LC-QTOF-MS approach shows potential for accurate body fluid/tissue identification in forensic science.
• Metabolite profiling offers a promising alternative to conventional BFI methods.
• This pilot study demonstrates the feasibility of using metabolomics for forensic casework.