posted on 2021-12-27, 15:37authored byAllix
M. Coon, A. John Dane, Gavin Setzen, Robert B. Cody, Rabi A. Musah
Earwax is a readily
accessible biological matrix that has the potential
to be used in disease diagnostics. However, its semisolid nature and
high chemical complexity have hampered efforts to investigate its
potential to reveal disease markers. This is because more conventional
methods of analysis such as gas chromatography–mass spectrometry
(GC–MS) and liquid chromatography–mass spectrometry
yield unsatisfactory results due to the presence of many nonvolatile
and/or coeluting compounds, which in some cases have very similar
mass spectrometric profiles. In addition, these routine methods often
require the sample to be saponified, which dramatically increases
the complexity of the analysis and makes it difficult to determine
which compounds are actually present versus those that are produced
by saponification. In this study, two-dimensional GC mass spectrometry
(GC × GC–MS) was successfully applied for the characterization
of the chemical components of earwax from healthy donors using nonpolar
(primary) and midpolar (secondary) columns without saponification.
Over 35 of the compounds that were identified are reported for the
first time to be detected in unsaponified earwax. The resulting GC
× GC–MS contour plots revealed visually recognizable compound
class clusters of previously reported groups including alkanes, alkenes,
fatty acids, esters, triglycerides, and cholesterol esters, as well
as cholesterol and squalene. The application of GC × GC–MS
revealed results that provide a foundation upon which future studies
aimed at comparing healthy donor earwax to that from individuals exhibiting
various disease states can be accomplished.