Detection of saliva on combustible and electronic cigarettes using the SERATEC Amylase Test and subsequent DNA analysis
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Citation
Abstract
Saliva can be detected on items including cigarette butts, glassware, clothing,
human skin and condoms, and the identification of saliva on these types of evidence may
be important to provide linkages or investigative leads in forensic cases. Sometimes when
the presence of saliva is indicated, the item will be sent for deoxyribonucleic acid (DNA)
analysis and may be used for identification of individuals involved in a crime. The
detection of saliva mostly depends on the activity and the presence of amylase. The
SERATEC® Amylase Test (SERATEC GmbH, Goettingen, Germany) is a lateral flow
immunochromatographic test that targets the presence of human α-Amylase using two
monoclonal anti-human-α-Amylase antibodies. This study investigates the effectiveness
of using the SERATEC® Amylase Test to detect amylase on cigarette butts and vaping
devices. In addition, the possible correlation between the SERATEC® Amylase Test result
and the amount of DNA extracted from cigarette butt samples is evaluated.
Results indicated that the cigarettes and vaping devices tested had no inhibitory
effect on the SERATEC® Amylase Test. The SERATEC® Amylase test was able to detect
amylase from various brands of cigarettes, marijuana cigarettes, JUULpods™ (JUUL
Labs™ Inc., San Francisco, CA) and an additional vaping device. Negative amylase test
results (22 of 114 samples) may be attributable to personal smoking habits and the texture
of the cigarette butt wrap paper or vaping device. DNA quantification results indicated
that the majority of cellular material was retained on the wrap paper even after submersion
in the SERATEC® Amylase Test buffer. It is recommended that the wrap paper from the
cigarette filter and the remaining extract from preliminary testing be combined prior to
DNA extraction in order to maximize total DNA recovered from a cigarette sample. The
correlation between the SERATEC® Amylase Test result and the quantity of DNA
extracted from the same source was not linear. The presence of saliva and DNA
concentration are controlled by different factors, thus using the detection of saliva to
predict the recoverability of DNA on cigarettes may be valuable in some situations, but is
not precise.