2023-07-312023-07-312016ROMÃO, Wanderson et al. Petroleomics by direct analysis in real time-mass spectrometry. Journal of the American Society for Mass Spectrometry, Washington, v. 27, n. 1, p. 182-185, 2016. DOI: 10.1007/s13361-015-1266-z. Disponível em: https://pubs.acs.org/doi/pdf/10.1007/s13361-015-1266-z. Acesso em: 28 jun. 2023.1044-0305e- 1879-1123https://pubs.acs.org/doi/pdf/10.1007/s13361-015-1266-zThe analysis of crude oil and its fractions by applying ambient ionization techniques remains underexplored in mass spectrometry (MS). Direct analysis in real time (DART) in the positive-ion mode was coupled to a linear quadrupole ion trap Orbitrap mass spectrometer (LTQ Orbitrap) to analyze crude oil, paraffin samples, and porphyrin standard compounds. The ionization parameters of DART-MS were optimized for crude oil analysis. DART-MS rendered the optimum conditions of the operation using paper as the substrate, T = 400°C, helium as the carrier gas, and a sample concentration ≥6 mg mL-1. In the crude oils analysis, the DART(+)-Orbitrap mass spectra detected the typical N, NO, and O-containing compounds. In the paraffin samples, oxidized hydrocarbon species (Ox classes, where x = 1–4) with double-bond equivalent of 1–4 were detected, and their structures and connectivity were confirmed by collision-induced dissociation (CID) experiments. DART(+)–MS has identified the porphyrin standard compounds as [M + H]+ ions of m/z 615.2502 and 680.1763, where M = C44H30N4 and C44H28N4OV, respectively, based on the formula assignment and by phenyl losses observed on CID experiments.engAcesso RestritoAmbient mass spectrometryDARTCrude oilParaffinPorphyrinArtigo10.1007/s13361-015-1266-z