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5
Amore dramatic example of automated peak find and spectral deconvolution is seen in Figure 4
where aminor peak (diethylaniline) is buried underneath a huge peak. Not only was thisminor
compound located underneath the large 2-phenoxyethanol peak, but a deconvolutedmass
spectrumwas produced that had excellent similarity with a librarymass spectrum.
2-Phenoxyethanol
Diethylaniline
Raw
mass spectrum
Deconvolutedmass spectrum
NIST Library
mass spectrum
Figure4.
Automated peak find and spectral deconvolution for diethylaniline in the presence of
2-phenoxyethanol in amix of blue ballpoint pen inks. Note that the rawmass spectrum taken at
the peak apex for diethylaniline is characteristic of 2-phenoxyethanol due to its high concentration.
The deconvoluted spectrum for diethylanilinematches well with the library spectrum.
The aging of documents created or signedwith ballpoint pens is often done by "calibrating" how
certain ink components decrease over time. For the aged ink experiment in this work,
2-phenoxyethanol was chosen formonitoring because it is the principal solvent inmany ballpoint
ink formulations. Preliminary experiments showed that the 2-phenoxyethanol concentration in an
ink scribble (as sampled by ambient temperature SPME) dropped rapidly and stabilized (Figure 5).
This observationwas confirmedwith older ink samples also, as shown in Figure 6.
