Determination of Carbonyl Functional Groups in Bio-Oils by Potentiometric Titration: The Faix Method

Jack Ferrell, Stuart Black

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations


Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 °C.

Original languageAmerican English
Article numbere55165
Number of pages5
JournalJournal of Visualized Experiments
Issue number120
StatePublished - 7 Feb 2017

Bibliographical note

Publisher Copyright:
© 2017 Journal of Visualized Experiments.

NREL Publication Number

  • NREL/JA-5100-66917


  • Analysis
  • Analytical
  • Bio-oil
  • Carbonyl
  • Chemistry
  • Issue 120
  • Pyrolysis
  • Titration


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