Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Brooke Baumgarten, M.S. - University of Central Florida
Co-Author(s): Nancy Flynn, B.A., University of Central Florida, Orlando, FL; Mark Marić, Ph.D., University of Central Florida, Orlando, FL; Santana Thomas, Ph.D., University of Central Florida, Orlando, FL; Candice M. Bridge, Ph.D., National Center for Forensic Science, University of Central Florida, Orlando, FL.
Unfortunately, sexual assaults are a reality in today’s society. Due to the understanding that DNA from seminal fluid is one of the main forms of evidence used to connect a suspect to a victim or crime scene, there has been an increased use of condoms in sexual assault cases. This dilemma has led to research into other types of trace evidence, e.g. sexual lubricants. Current research is being performed to determine the length and optimal conditions appropriate for storing trace lubricant residue before the samples degrade and pattern becomes unrecognizable. Prior to conducting this study, it was necessary to determine how long the samples could be stored in the freezer in the event that the samples cannot be analyzed on collection day. Therefore, a two-week study was first performed to determine the longevity of extracted lubricants when stored within solvents at -20°C. Secondly, a preliminary cotton swab optimization study was completed to determine which swab yielded the most effective lubricant extraction and least background noise. Afterwards, sexual lubricant from a condom and a personal bottled lubricant were deposited onto respective cotton swabs to be stored and evaluated under different conditions. This research project used direct analysis in real time – high resolution mass spectrometry (DART-HRMS), gas chromatography – mass spectrometry (GC-MS), and Fourier transform infrared spectroscopy (FTIR) protocols to analyze the stored swabs containing sexual lubricants at time points: 0, 1, 7, and 30 days. At each time point, blank, personal lubricant, and condom swabs were stored at 35°C, 22°C at about 100% humidity, 22°C at about 50% humidity, 22°C at about 0% humidity, 4°C, and -20°C. Storage of swabs at these conditions allowed for the determination of lubricant degraded and adversely affected the ability to recognize classification patterns at the simulated environmental conditions. Each swab was extracted and analyzed in triplicate via DART-HRMS and FTIR, and in duplicate by GC-MS. The resulting spectra from each instrument can be used to classify unknown lubricant samples and generate investigative leads. Multivariate statistical techniques were used to compare stored and neat samples to determine if chemical breakdown for each lubricant occurred and if the pattern changed significantly. Preliminary results suggest that the general profile of the lubricant does not change, however, the concentrations of components may decrease over time. Analysis of stored sexual lubricants within different environments over time via DART-HRMS, GC-MS, and FTIR may be beneficial to the forensic community by allowing investigators and examiners to identify the optimal condition for storage. Additionally, the ability to understand the effects of environment and time to the analysis of sexual lubricants may offer helpful information when analyzing sexual assault kits and provide a link for investigators between a suspect and crime scene.
Funder Acknowledgement(s): The research presented is funded by the National Institute of Justice [2018-MU-BX-0002] and the state of Florida.
Faculty Advisor: Candice Bridge, firstname.lastname@example.org
Role: I performed all the experimental set up and preparation, as well as set up all the protocols for the sample analysis. I performed all sample analysis by gas chromatography ? mass spectrometry and performed data analysis and multivariable statistics on procured data. I also performed the preliminary swab optimization study, as well as contributed to the setup and analysis of the preliminary longevity study.