Characterization of non-ideal blending in infrared spectra of gasoline surrogates

Emad Al Ibrahim*, Houssem Eddine Rekik, Aamir Farooq

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Infrared spectroscopy is a popular tool for fuel characterization. This study sheds light on the non-ideal blending of typical fuel surrogate components. We measure Attenuated Total Reflection Fourier-transform Infrared (ATR-FTIR) spectra of 230 liquid blends with varying compositions of n-heptane, iso-octane, ethanol, toluene, methyl-cyclohexane, 1-hexene, and cyclopentane. We report frequency shifts and excess absorbance for Primary Reference Fuels (PRFs) and their blends with ethanol, toluene, and multi-component mixtures. We showcase a variety of quantitative methods, starting with the simple Beer–Lambert linear fits, for the prediction of blend composition. We also provide calibration curves that account for non-linear blending effects, and use these to correct simulated spectra. Lastly, we discuss chemometric methods and their accuracy and robustness to interference and noise. Beyond concentrations, we predict functional groups, molecular weight, and branching index, which transform the mixture spectra to a unified basis.

Original languageEnglish (US)
Article number128134
StatePublished - Jul 15 2023

Bibliographical note

Funding Information:
This work was funded by the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST), Saudi Arabia .

Publisher Copyright:
© 2023 Elsevier Ltd


  • e-fuels
  • Excess absorption
  • Frequency shift
  • Functional groups
  • Gasoline
  • Non-ideal blending
  • Surrogates

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry


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