Characterization of Naphthenic Acid Singly Charged Noncovalent Dimers and Their Dependence on the Accumulation Time within a Hexapole in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

Naphthenic acids are believed to be responsible for a number of unwanted phenomena occurring during the processing and transport of crude oil, such as pipeline corrosion and precipitation of calcium salts. In this paper, Fourier transform ion cyclotron resonance mass spectrometry is used to analyze a mixture of naphthenic acids. Naphthenic acids have been shown to form multimers, and the study of multimer association could lead to a better understanding of naphthenic acid phase behavior in crude oil production systems. The dependence of the signal intensity of such aggregates on the accumulation time within the ion source hexapole has been studied, and it has been highlighted that such a dependence suggests a noncovalent interaction as the primary cause for aggregation. This would account for the decrease in signal intensity with accumulation time as a result of the increasing chance of undergoing collisional dissociation. The nature, role and behaviour of naphthenic acid dimers may be better understood by the application of mass spectrometry and this has potential to be applied to samples of importance to the oil industry.

Beyond Naphthenic Acids: Environmental Screening of Water from Natural Sources and the Athabasca Oil Sands Industry Using Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Homologous series for ions with DBE of 3.5 and 4.5 (corresponding to neutral species with Z = -4 and Z = -6, respectively) were particularly pronounced for the O 2 class for the groundwater and OSPW samples, with strong contributions additionally for ions with DBE of 7.5 (Z = -12), as has been previously observed [9,12,15,17]. The carbon number ranges for the O 2 and O 4 classes are similar for each sample, thus indicating that the O 4 components are not dimers, based upon O 2 class precursors [44,45]. When considering the O 4 class, ions with a DBE of 4.5 and 5.5 (Z = -6 and Z = -8, respectively) were amongst the most intense for the groundwater and OSPW samples, and it is noteworthy that this represents an increase of 1 …”

Ion Accumulation Time Dependent Molecular Characterization of Natural Organic Matter Using Electrospray Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…42 Da Campo et al reported that extending the IAT could partially destroy noncovalent interactions between dimers of naphthenic acids by an increase in the number of collisions in the hexapole. 43 Since NOM contains a high functional group content including carboxylic, phenolic, ketonic, and polyaromatic moieties and could form supramolecular aggregation in aqueous solution by noncovalent interactions, 15−17 fragmentation of molecules in NOM or dissociation of NOM aggregations may occur by extending IAT to form the third series of peaks. The second possible pathway is that the third series of peaks may be caused by space-charge frequency shifts of the first series of ions in NOM during MS detection.…”

Observation of CO2 and solvent adduct ions during negative mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of monohydric alcohols

“…The presence of O3 and O4 species ions leads to a critical problem for characterization of monohydric alcohols by ESI FT‐ICR MS. Previous studies showed that the cone and extraction voltages, collision voltages and accumulation time, and bias voltage affected the intensities of the adduct ions or bonding ion signals. To investigate the effect on mass spectra of the collision energy, synthetic monoalcohols were analyzed with CID experiments at various collision energy.…”