Investigation of dissociation constants for individual and total naphthenic acids species using ultra performance liquid chromatography ion mobility time-of-flight mass spectrometry analysis

Huang, Rongfu; Chelme-Ayala, Pamela; Zhang, Yanyan; Changalov, Mohamed; El-Din, Mohamed Gamal

doi:10.1016/j.chemosphere.2017.06.067

Cited by 9 publications

(1 citation statement)

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“…In electrospray ionization, the efficiency of ionization is affected by several molecular properties such as p K a , hydrophobicity, and surface activity . The p K a of O 3 – - and O 4 – -containing species is greater than that of O 2 – , and it has been suggested that O 3 – and O 4 – are addition of extra oxygen atoms to O 2 – –NAs species, and present as hydroxyl groups [i.e., O 4 – –NAs exist as (OH) 2 –NAs] ,, compared to the other assumption that O 4 – are dicarboxylic acids . Lesser intensity of O 2 – species observed under acidic conditions (i.e., pH 2) in ABN, LLE, and C 18 compared to basic conditions might be due to the greater concentration of O 4 – observed under acidic conditions (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Comparison of the Effects of Extraction Techniques on Mass Spectrometry Profiles of Dissolved Organic Compounds in Oil Sand Process-Affected Water

Alharbi

Morandi²,

Jones³

et al. 2019

Energy Fuels

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Recent advances in mass spectrometry have facilitated chemical characterization and profiling of complex environmental mixtures such as oil sand process-affected water (OSPW) and identification of previously unresolved chemicals. However, because OSPW is a complex mixture of salts, metals, suspended particulate matter, and dissolved organics, extraction techniques are required to reduce the effects of signal suppression/enhancement. In this work, Orbitrap, ultrahigh resolution mass spectrometry was used to perform a comprehensive comparison of solid phase extraction (SPE) and liquid−liquid extraction (LLE) techniques on profiling of dissolved organic chemicals in OSPW. When operated in negative ion mode, extraction of naphthenic acid (NAs−O 2 ) was dependent on acidification of OSPW samples for C 18 and LLE techniques. However, when applying a hydrophilic lipophilic balance (HLB) sorbent (ABN) SPE technique, the extractability of NAs was independent of pH. When operated in positive ion mode, for all extraction methods, nitrogen-and sulfur-containing species were more abundant and diverse in basic extracts than in acidic extracts and ABN extracted the greatest number of chemical species including nitrogen-, sulfur-, and oxygen-containing species. Overall, this study supports the utility of HLB SPE techniques for profiling of species of dissolved organic chemicals in OSPW at environmentally relevant pH.

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