FORENSIC SCIENCES: CRIMINALISTICS - Bio Medical Forensics

instability of semen. Specifically, acid phosphatase activity was detected
in all condom types for semen stored up to two weeks; only two
lubricated condoms gave negative results. In comparison, acid
phosphatase activity was detected in a majority of the non-lubricated
condoms and some of the spermicidal condoms stored between 7-9
months. However, acid phosphatase activity was not detected in any of
the lubricated condoms stored over a comparable time period. No major
spermatozoa morphological changes or concentration decreases were
observed for the samples stored in the short-term study. However, for
samples stored in the long-term study, both non-lubricated and lubricated
condoms primarily exhibited head and tail separation. The morphology
of the heads associated with the lubricated samples appeared grainy
suggesting compromised membrane structure. In contrast, spermatozoa
were difficult to locate in samples stored in the spermicidal condoms.
The heads that were identified appeared to have a grainy and tulip-shaped
silhouette, again suggesting a compromised cellular membrane. Full
mtDNA profiles were recovered from all samples tested, regardless of the
type of condom used to store the semen. There was a noticeable decrease
in the intensity of the profile for the long-term study samples. NuDNA
was recovered for all samples; however, there was a decrease in the
amount recovered as the duration of storage increased.
The results of the present study suggest that condoms have a
negative affect on the stability of seminal fluid; however, nuDNA and
mtDNA was recovered from all the samples. This suggests that there may
be other factors (besides nuclease activity) contributing to the degradation
of seminal fluid in condoms.
Semen Identification, Condoms, Genotyping
A99 Comparative Analysis of Condom
Lubricants in Pre- and Post- Coital Swabs
by Accurate Time-of-Flight – Direct Analysis
in Real Time
Lesley A. Huggings, BS*, John Jay College of Criminal Justice, 445 West
59th Street, #4405, New York, NY 10019; and Gloria Proni, PhD, John
Jay College of Criminal Justice, Science Department, 445 West 59th
Street, 10019, New York, NY 10019
After attending this presentation, attendees will understand how a
commercially available time-of-flight instrument, a very sensitive and
accurate state-of the-art mass spectrometer, may be used to analyze
vaginal swab and condom residues obtained by volunteers before and
after intercourse. In particular, this study uses in vivo samples for the
analysis (vaginal swabs after intercourse) in order to mime a rape
situation.
This presentation will impact the forensic science community
because this analysis put the basis for the application of this
instrumentation to analyze biological samples obtained in rape cases. The
implementation of this technique in forensic analysis is also a key point
of this work.
In the last several years the number of sexual assaults in which the
perpetrator used a condom has dramatically increased. Condom
lubricants can be polyethylene glycol (PEG)-based or silicone-based.
Polyethylene glycol is a non-ionic water-soluble polymer of ethylene
oxide whose viscosity depends on the chain length. The compound is
water-soluble and can therefore easily pass across mucous membranes,
limiting its forensic detection. Silicone-based lubricants are found on
most lubricated condoms, they are not absorbed into the skin or across
membranes, thus staying on the surface to provide lasting slipperiness. It
* Presenting Author
is this characteristic that makes it of great forensic value. Its major
ingredient is PDMS (polydimethylsiloxane), a silicone-based organic
polymer, which is a mixture of oligomeres ranging in molecular weights
up to 20,000 amu. The oligomeres have a limited number of monomer
units while polymers can have an unlimited number of monomer units.
The spermicide most commonly found in condom lubricants is the
detergent nonoxynol-9. It is a non-ionic surfactant and is typically a harsh
detergent, but is found in condom lubricants at concentrations ranging
from 5% to 10%. In sexual assault cases, lubricants and polymers
recovered from the crime scene may provide useful information for the
investigation, particularly when DNA evidence is not available.
Individuals, generally, use condoms to be protected by sexually
transmitted diseases and to prevent identification from the deposited
semen. Several techniques have been used in the past to analyze traces
left by condoms: Raman spectroscopy, 1 gas chromatography – mass
spectrometry, 2 infrared spectroscopy, 3 nuclear magnetic resonance, 4 and
capillary electrophoresis. 5 In this research, the instrument has been used
to determine differences between commercially available condoms. The
lubricant from condoms sold in the United States were collected using a
specially designed glass apparatus and analyzed directly, without any
manipulation, with the instrument in order to obtain pre-coital data and to
differentiate between the condoms. Data obtained from vaginal swabs
obtained before sexual activity will be presented: these data were used in
the study as a blank. The traces obtained from vaginal swabs in postcoital
conditions were also analyzed by means of the same technique.
Due to interference from the background in the post-coital vaginal swabs
and an overall low sample yield, the vaginal swab samples were also
extracted using different polar and non-polar solvents in an attempt to
increase signal power. Data derived from the extraction step will be also
presented. Volunteers have been recruited to obtain the vaginal swabs
before and after intercourse and several brands of condoms were used in
the analysis. The overall goal of the project was to be able to
individualize the condoms and consequently be able to discriminate
between the brands and consequently collect useful information that
could be used in sexual assault cases.
References:
1 J. Wolfe, B.S. and D. L. Exline, M.S.F.S., J. Forensic Sci,. 2003, vol.
48, No. 5 pp. 1 - 8
2 P. Maynard, K. Allwell, C. Roux, M. Dawson, D. Royds, Forensic.
Sci. Int., 2001, Vol. 124, pp. 140-156
3 G. P. Campbell, M. Sc. (Hons) and A. L. Gordon, M. Sc. (Hons), J.
Forensic Sci, 2007, vol. 52, no. 3, pp 630 – 642
4 G. S. H. Lee, Ph.D., K. M. Brinch. BSc, K. Kannangara, Ph.D., M.
Dawson, Ph.D., M. A. Wilson, D.Sc., J. Forensic Sci,. 2001, vol. 46,
No. 4 pp. 808 - 821
5 F. Burger, M. Dawson, C. Roux, P. Maynard, P. Doble, P. Kirkbride,
Talanta, 2005, vol. 67, pp 368-376
Time-of-Flight, Vaginal Swab, Condom’s Residue
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