Ambient Electric Arc Ionization for Versatile Sample Analysis Using Mass Spectrometry

A novel, convenient ambient electric arc ionization (AEAI) device was developed as mass spectrometry ion source for versatile sample analysis. AEAI could be considered as a soft ionization technique in...

Exploring the extra-virgin olive oil volatilome by adding extra dimensions to comprehensive two-dimensional gas chromatography and time of flight mass spectrometry featuring tandem ionization: validation of ripening markers in headspace linearity conditions

Background Comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOF MS) is the most informative analytical approach for chemical characterization of the complex food volatilome. Key analytical features include: separation power and resolution enhancement; improved sensitivity; and structured separation patterns from chemically correlated analytes. Objective In this study, we explore the complex extra-virgin olive oil volatilome by combining head-space (HS) solid-phase microextraction, applied under HS linearity conditions to GC×GC-TOF MS featuring hard and soft ionization in tandem. Methods Multiple analytical dimensions are combined in a single run and evaluated in terms of: chemical dimensionality; method absolute and relative sensitivity; identification reliability provided by spectral signatures acquired at 70 and 12 eV; and dynamic and linear range of response provided by soft ionization. Results Method effectiveness is validated on a sample set of oils from Picual olives at different ripening stages. Ripening markers (3,4-diethyl-1,5-hexadiene (RS/SR), 3,4-diethyl-1,5-hexadiene (meso), (5Z)-3-ethyl-1,5-octadiene, (5E)-3-ethyl-1,5-octadiene, (E,Z)-3,7-decadiene and (E,E)-3,7-decadiene, (Z)-2-hexenal, (Z)-3-hexenal and (Z)-3-hexenal, (E)-2-pentenal, (Z)-2-pentenal, 1-pentanol, 1-penten-3-ol, 3-pentanone, and 1-penten-3-one) and quality indexes ((Z)-3-Hexenal/Nonanal, (Z)-3-Hexenal/Octane, (E)-2-Pentenal/Nonanal, and (E)-2-Pentenal/Octane) are confirmed for their validity in HS linearity conditions. Conclusions : For the complex olive oil volatilome, the proposed approach offers concrete advantages for the validation of the informative role of existing analytes while suggesting new potential markers to be studied in larger sample sets. Highlights The accurate fingerprinting of volatiles by HS-SPME operating in HS linearity conditions followed by GC×GC-TOF MS featuring tandem ionization gives the opportunity to improve the quality of analytical data and reliability of results.

Matrix-assisted nanoelectrospray mass spectrometry for soft ionization of metal(i)–protein complexes

Metal ions play significant roles in biological processes, and investigation of metal–protein interactions provides a basis to understand the functions of metal ions in such systems.