Direct exposure mass spectrometry

Case Studies Direct Exposure-Mass Spectrometry (DE-MS)... 

In addition to GC/MS, high performance liquid chromatography (HPLC/MS) has been used to analyse natural resins in ancient samples, particularly for paint varnishes containing mastic and dammar resins [34]. A partial limitation of chromatographic techniques is that they do not permit the analysis of the polymeric fraction or insoluble fraction that may be present in the native resins or formed in the course of ageing. Techniques based on the direct introduction of the sample in the mass spectrometer such as direct temperature resolved mass spectrometry (DTMS), direct exposure mass spectrometry (DE-MS) and direct inlet mass spectrometry (DI-MS), and on analytical pyrolysis (Py-GC/MS), have been employed as complementary techniques to obtain preliminary information on the... 

This review provides an up-to-date overview of the application of analytical procedures based on MS for the characterization of organic natural materials in archaeological and historical objects. Applications that feature the use of gas chromatography/mass spectrometry (GC/MS), Py-GC/MS, high performance liquid chromatography combined with mass spectrometry (HPLC/MS), and direct MS analysis such as matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS), and direct exposure mass spectrometry (DE-MS) are sununarized to highlight the different information provided by each of the various analytical approaches. Case studies and examples are also presented and include a description of the molecular markers and of the molecular profiles that are used to identify the original materials. 

Modugno, E, Ribechini, E., Calderisi, M., Giachi, G., Colombini, M.P. (2008) Analysis of lignin from archaeological waterlogged wood by direct exposure mass spectrometry (DE-MS) and PCA evaluation of mass spectral data. Microchemical Journal, 88,186-193. 

M.P. Colombini, F. Modugno, E. Ribechini, Direct exposure electron ionization mass spectra metry and gas chromatography/mass spectrometry techniques to study organic coatings on archaeological amphorae, Journal of Mass Spectrometry, 40, 675 687 (2005). 

E. Ribechini, F. Modugno, M.P. Colombini, Direct exposure (chemical ionization) mass spectrometry for a rapid characterization of raw and archaeological diterpenoid resinous substances, Microchimica Acta, 162, 405 413 (2008). 

F. Modugno, E. Rihechini and M. P. Colomhini, Chemical study of triterpenoid resinous materials in archaeological findings hy means of direct exposure electron ionisation mass spectrometry and gas chromatography/mass spectrometry, Rapid Commun. Mass Spectrom., 20, 1787 1800 (2006). 

Direct introduction of a sample, either in solid or liquid state, in the ion source of a mass spectrometer may be achieved through two procedures the first one is based on the use of a direct insertion probe (DIP) the second one necessitates a direct exposure probe (DEP). Direct introduction followed by heating of the sample in the ion source of the mass spectrometer is also known as direct temperature resolved mass spectrometry (DTMS). 

Flamini, R. and Dalla Vedova, A. (2004) Fast determination of the total free resver-atrol content in wine by direct-exposure-probe, positive-ion-chemical-ionization and collisional-induced-dissociation mass spectrometry (DEP/PICI-MS/MS), Rapid Commun. Mass Spectrom. 18(17), 1925-1931. 

Mass spectrometry was also employed to confirm the structure of one Series 1 and one Series 2 compound, utilizing a Finnegan 4000 direct exposure probe mass spectrometer. 

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