US EPA

1468192 

Journal Article 

Observation of vanadyl porphyrins and sulfur-containing vanadyl porphyrins in a petroleum asphaltene by atmospheric pressure photonionization Fourier transform ion cyclotron resonance mass spectrometry 

Qian, K; Mennito, AS; Edwards, KE; Ferrughelli, DT 

2008 

1 

Rapid Communications in Mass Spectrometry
ISSN: 0951-4198
EISSN: 1097-0231 

JOHN WILEY & SONS LTD 

CHICHESTER 

22 

14 

2153-2160 

English 

18536070 

10.1002/rcm.3600 

WOS:000257863500002 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-47349107174&doi=10.1002%2frcm.3600&partnerID=40&md5=5f1217c61f3eb58362bad539c90f3a78
Exit
 

Vanadyl (VO) porphyrins and sulfur-containing vanadyl (VOS) porphyrins of a wide carbon number range (C(26) to C(52)) and Z-number range (-28 to -54) were detected and identified in a petroleum asphaltene by atmospheric pressure photonionization (APPI) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). APPI provides soft ionization of asphaltene molecules (including VO and VOS porphyrins), generating primarily molecular ions (M(+.)). The ultra-high mass resolving power (m/Delta m(FWHM) approximately 500 K) of FTICR-MS enabled resolution and positive identification of elemental formulae for the entire family of VO and VOS porphyrins in a complicated asphaltene matrix. Deocophylerythro-etioporphyrin (DPEP) is found to be the most prevalent structure, followed by etioporphyrins (etio)- and rhodo (benzo)-DPEP. The characteristic Z-distribution of VO porphyrins suggests benzene and naphthene increment in the growth of porphyrin ring structures. Bimodal carbon number distributions of VO porphyrins suggest possible different origins of low and high molecular weight species. To our knowledge, the observation of VOS porphyrins in a petroleum product has not previously been reported. The work is also the first direct identification of the entire vanadyl porphyrin family by ultra-high resolution mass spectrometry without chromatographic separation or demetallation.