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Characterization of oil sands naphthenic acids treated with ultraviolet and microwave radiation by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry
Author(s) -
Headley John V.,
Peru Kerry M.,
Mishra Sabyasachi,
Meda Venkatesh,
Dalai Ajay K.,
McMartin Dena W.,
Mapolelo Mmilili M.,
Rodgers Ryan P.,
Marshall Alan G.
Publication year - 2010
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4754
Subject(s) - chemistry , fourier transform ion cyclotron resonance , naphthenic acid , mass spectrometry , ultraviolet , electrospray , microwave , analytical chemistry (journal) , ion , extraction (chemistry) , fraction (chemistry) , irradiation , fourier transform infrared spectroscopy , nuclear chemistry , chromatography , organic chemistry , chemical engineering , corrosion , physics , quantum mechanics , nuclear physics , engineering
Naphthenic acids (NAs) are concentrated in oil sand process water (OSPW) as a result of caustic oil sands extraction processes. There is considerable interest in methods for treatment of NAs in OSPW. Earlier work has shown that the combination of ultraviolet (UV) and microwave treatments in the laboratory was effective in reducing the concentration of classical NAs. Here we apply Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) to further characterize NAs treated with (a) UV (254 nm) in the presence of TiO 2 catalyst; and/or (b) microwave irradiation (2.45 GHz). FT‐ICR MS was used to characterize the NA fraction before and after treatment. Acidic oxygen‐containing classes were most abundant in all samples whereas other heteroatomic classes were least abundant or not present in some samples. For example, the SO 2 ‐containing species were absent in UV‐ or combined UV‐ and microwave‐treated samples. The O 2 class was dominant in all samples, indicative of NAs. However, samples treated with UV and microwave radiation have a lower relative abundance of other heteroatomic classes. We observed O 2 , S 1 O 2 , O 3 , S 1 O 3 , O 4 , O 5 , and O 6 classes, whereas the species with relatively high O n content, namely, the O 3 , O 5 , and O 6 classes, were present only in UV‐ and microwave‐treated samples. The relatively high O n content is consistent with oxidation of the parent acids in treated samples. There may thus be potential implications for environmental forensics. For example, the monitoring of the ratio of SO 2 :O 2 or tracking the relative abundances of O 2 , O 3 , O 4 , O 5 , and O 6 classes may provide insights for distinguishing naturally derived oil sands components from those that are process‐related in aquatic environments. Copyright © 2010 John Wiley & Sons, Ltd.