Quantitative measurement of complex substances dissolved in an ionic liquid using IR spectroscopy and chemometrics

Johannes Kiefer* (Corresponding Author), Andreas Boesmann, Peter Wasserscheid

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In the past two decades, ionic liquids have found many applications as solvents for complex solutes. Prominent examples are the dissolution of biomass and carbohydrates as well as catalytically active substances. The chemical analysis of such solutions, however, is still a challenge due to the molecular complexity. In the present work, the use of infrared spectroscopy for quantifying the concentration of different solutes dissolved in an imidazolium-based ionic liquid is investigated. Binary solutions of glucose, cellubiose, and Wilkinson's catalyst in 1-ethyl-3-methylimidazolium acetate are studied as examples. For this purpose, different chemometric approaches (principal component analysis (PCA), partial least-squares regression (PLSR), and principal component regression (PCR)) for analyzing the spectra are tested. Principal component analysis was found to be suitable for classifying the different solutions. Both regression techniques were capable of deriving accurate concentration values. The performance of PLSR was slightly better than that of PCR for the same number of components.

Original languageEnglish
Pages (from-to)32-37
Number of pages6
JournalTm-Technisches messen
Issue number1
Early online date20 Dec 2016
Publication statusPublished - Jan 2017
EventIEEE Workshop on Industrial and Medical Measurement and Sensor Technology (SENSORICA) - Mulheim, Germany
Duration: 16 Jun 201617 Jun 2016


  • FTIR
  • principal component analysis
  • regression
  • compositional analysis


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