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One of the most difficult tasks facing analytical chemists is the
identification of the natural organic products found in museum artifacts
and archaeological sites. The list of such materials is endless:
oils, resins, waxes, plant gums, tempera, glue, casein, glair, dyes,
amber, and food residues. The solutions to problems in conservation
science and archaeometry frequently hinge on a comprehensive identification
of these very materials. One analytical method that has been successfully
applied by CCI and other conservation science laboratories around
the world is gas chromatography/mass spectrometry—or GC/MS.
The general approach of GC/MS is to separate components of a mixture
and identify them based on their characteristic mass spectra. The
GC separation involves the partitioning of a mixture between a moving
gas phase and a stationary phase. This is followed by the breakdown
of individual compounds into a characteristic pattern of fragments
in the mass spectrometer. The challenge for chemists at CCI is that
the samples they receive are not only extremely small but are typically
contaminated and oxidized or polymerized; this leaves only a small
fraction of components that can be analysed by GC/MS.
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CCI has recently acquired an Agilent (formerly Hewlett
Packard) HP 6890 Plus Gas Chromatograph system with an HP 5973 mass
selective detector, and hired scientist Geneviève Sansoucy
to work with the instrument. This new system (which replaces an aging
one) complements the existing Fourier transform infrared spectrometers
and high performance liquid chromatograph, and allows CCI to conduct
more accurate and thorough analyses of a wide range of materials. |
