National Center for Forensic Science

Lubricants

Forensic analysis of lubricants consists of the examination lubricant residue collected after a sexual assault. Lubricants can be collected from a variety of places, including: from the victim, from the suspect, from the condom/condom wrapper that was used in the assault or from bed sheets. These residues are analyzed to determine if they two samples have common components which could provide a basis for stating that there was contact during a sexual assault.

Submitted samples can be submitted directly from the crime scene (i.e. used condom or condom wrapper) or in a sexual assault kit (i.e. biological swabs). Determining if two samples have the same components can be accomplished by determining the presence of a spermicide (nonoxynol-9) by analyzing the organic extract via gas chromatography-mass spectrometry (GC-MS), identifying the presence of a major lubricant (e.g. PDMS or PEG) using infrared (IR) spectroscopy, and the presence of dry lubricants via polarized light microscopy. Samples considered to be from a similar source can be determined if both the known and the unknown have similar components.

NCFS lubricant research:

1.Characterization of lubricant classes by direct analysis in real time – mass spectrometry (DART-MS)

2.Identifying of degradation pathways of lubricants

3.Comparison of lubricants types by application of chemometrics to DART-MS, GC-MS, and IR data.

For more information contact Dr. Candice Bridge.