Examination of Firearms Review: 2007 to 2010 - Interpol

could be distinguished from lower mass-to-charge (m/z) species typically
generated from other constituents in paint formulations.[321] Lastly, Kirby et al.
reported on the use of laser desorption mass spectrometry for synthetic organic
pigments as employed in works of art.[322]
23. Capillary Electrophoresis (CE)
Compared to GC, CE requires simpler sample pretreatment (does not require
derivatization) but the separation efficiency and detection sensitivity is not as
good. Two separate studies describe these differences. To demonstrate how
CE can be used successfully, Kaml and Kenndler described using CE for the
analysis of natural organic binding media.[323] Findeisen and coauthors
analyzed diterpenoic acids used in coatings and varnishes.[324]
24. Liquid Chromatography (LC)
The final separation technique applied to paint analysis was liquid
chromatography. Checa-Moreno et al. used HPLC with a diode array detector
(DAD) to identify proteinaceous binders. In such an application, traditional
means of identification are prone to difficulty. Therefore, SIMCA (soft
independent modeling of class analogy) was evaluated and compared to the
more traditional strategies.[325] In their research, Leo and coauthors used nano
LC-MS/MS with ESI to further apply proteomic strategies to the identification of
proteins in paintings.[326]
25. Matrix-assisted laser desorption ionization - time of flight mass
spectrometry (MALDI-TOF)
Researchers have demonstrated that MALDI-TOF can be utilized in paint
analyses. Kuckova and coauthors identified proteinaceous binders in very small
samples and discussed how MALDI-TOF can distinguish among main binder
classes, is a relative speedy technique, and has low cost following the purchase
of the MS.[327] Soltzberg et al. used the technique in both positive and negative
modes to characterize dyes and pigments. The technique provided a convenient
and versatile method for such a purpose.[328]
In two separate publications, Hoogland and Boon combined MALDI with nano-
ESI-MS to analyze poly(ethylene glycol) additives in acrylic artists’ paints. In the
Method development and application of the technique to paints in described in
the two papers. In some instances, the authors assert that it was possible to
suggest a specific brand of paint.[329;330]
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