New challenges for electron ionization-mass spectrometry.

 

Pierangela Palma, Veronica Termopoli, Giorgio Famiglini, Maurizio Piergiovanni, Achille Cappiello

 

Università di Urbino Carlo Bo, Dipartimento di Scienze Pure ed Applicate, LC-MS Group, Piazza Rinascimento 6 – 61029 Urbino (PU)

 

In electron ionization (EI) mass spectrometry (MS) the analytes are ionized in the gas-phase by means of high-energy electrons. The high energy involved in the ionization process also promotes the extensive fragmentation of the molecule. Highly reproducible and characteristic spectra of the analytes can be collected and compared against library reference spectra for compound identification. EI is the standard technique used in gas chromatography (GC)-MS. Solvent and sample restrictions cause difficulties in creating a similar EI-based liquid chromatography (LC)-MS interface. Our research group developed an LC-MS interface, called Direct-EI, which combines, in a single instrument, the identification advantages of library searchable EI spectra with the separation power of an LC column, with no matrix effects and no need of a high-resolution instrument [1, 2]. Recently, a new interface design called “Liquid-EI”, LEI, was developed by our group, in which the vaporization of the LC eluate is carried out inside a micro-channel right before entering the ion source [3]. An overview of different applications of forensic interest, involving the three aforementioned techniques, is presented: 1) the determination of targeted and non-targeted compounds in human brain samples [4, 5, 6]; 2) the quali-quantitative assessment of benzodiazepines in drinks [7, 8].

 

References

[1] P. Palma, G. Famiglini, H. Trufelli, E. Pierini, V. Termopoli, A. Cappiello, Anal. Bioanal. Chem. 399, (8), 2683 (2011).

[2] A. Cappiello, G. Famiglini, P. Palma, E. Pierini, V. Termopoli, H. Trufelli, Mass Spectrom. Rev. 30, 1242 (2011).

[3] A. Cappiello, M. Piergiovanni, G. Famiglini, V. Termopoli, P. Palma, A. Cappiello “DEI vs. LEI: a novel, advanced system for interfacing liquid chromatography and electron ionization mass spectrometry.” Presented at the 64th ASMS Conference on Mass Spectrometry and Allied Topics, San Antonio, TX, USA, June 5-9, 2016.

[4] A. Cappiello, G. Famiglini, P. Palma, V. Termopoli, A. M. Lavezzi, L. Matturri, Anal. Bioanal. Chem. 406, 2779 (2014).

[5] V. Termopoli, G. Famiglini, P. Palma, L. Magrini, A. Cappiello, Anal. Bioanal. Chem. 407, 2463 (2015).

[6] V. Termopoli, G. Famiglini, P. Palma, A. Cappiello “UHPLC-Liquid-EI-MS/MS interface: a new frontier of multiclass environmental risk factors assessment in sudden infant death syndromes.” Presented at the 64th ASMS Conference on Mass Spectrometry and Allied Topics, San Antonio, TX, USA, June 5-9, 2016.

[7] G. Famiglini, F. Capriotti, P. Palma, V. Termopoli, A. Cappiello J. Anal. Toxicol. 39 (4), 306-312 (2015).

[8] G. Famiglini, V. Termopoli, P. Palma, A. Cappiello Electrophoresis 37 (7-8), 1048 (2016).