title: Petroleomics by EASI(+/-) FT-ICR MS.
abstract: An ambient ionization/desorption technique, namely, easy ambient sonic-spray ionization mass spectrometry (EASI), has been applied to crude oil samples. From a single droplet of the sample placed on an inert surface, EASI(+/-) is shown to promote efficient desorption and ionization of a myriad of polar components via the action of its cloud of very minute supersonic bipolar charged droplets. The gaseous [M + H](+) and [M - H](-) ions concurrently formed by EASI(+/-) were analyzed by Fourier transform mass spectrometry (FT-ICR MS), and a total of approximately 6000 acidic and basic components have been attributed. EASI(+/-) FT-ICR MS of crude oils is show to be almost as fast as ESI(+)/ESI(-) FT-ICR MS, providing similar compositional information of polar components and spectral quality comparable to that of a commercial nonochip-based robotic ESI device. EASI(+/-) requires no sample workup thus eliminating risks of contamination during sample manipulation and memory effects because of carry over in pumping ESI lines. More importantly, EASI(+/-) is a voltage-free ionization technique therefore eliminating risks of redox processes or duality of ionization mechanisms that can be observed in voltage-assisted processes. Data visualization via typical petroleomic plots confirms the similarity of the compositional information provided by EASI(+/-) compared to ESI(+)/ESI(-). The ambient EASI(+/-) FT-ICR MS method requires no voltage switching in changing the ion polarity mode, offering a workup, heating and voltage-free protocol for petroleomic studies performed at open atmosphere directly on the undisturbed crude oil sample.
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, University of Campinas-UNICAMP, Institute of Chemistry, 13083-970 Campinas, SP, Brazil.
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Corilo
authors.forename: Boniek G
authors.initials: BG
authors.lastname: Vaz
authors.forename: Rosineide C
authors.initials: RC
authors.lastname: Simas
authors.forename: Heliara D Lopes
authors.initials: HD
authors.lastname: Nascimento
authors.forename: Clécio F
authors.initials: CF
authors.lastname: Klitzke
authors.forename: Rosana C L
authors.initials: RC
authors.lastname: Pereira
authors.forename: Wagner L
authors.initials: WL
authors.lastname: Bastos
authors.forename: Eugênio V
authors.initials: EV
authors.lastname: Santos Neto
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Rodgers
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin