Comparison of Vibrational Spectroscopic Techniques for Quantification of Water in Natural Deep Eutectic Solvents

Vibrational spectroscopic techniques, i.e., attenuated total reflectance infrared (ATR-IR), near infrared spectroscopy (NIRS) and Raman spectroscopy (RS), coupled with Partial Least Squares Regression (PLSR), were evaluated as cost-effective label-free and reagent-free tools to monitor water content in Levulinic Acid/L-Proline (LALP) (2:1, mol/mol) Natural Deep Eutectic Solvent (NADES). ATR-IR delivered the best outcome of Root Mean Squared Error (RMSE) of Cross-Validation (CV) = 0.27% added water concentration, RMSE of Prediction (P) = 0.27% added water concentration and mean % relative error = 2.59%. Two NIRS instruments (benchtop and handheld) were also compared during the study, respectively yielding RMSECV = 0.35% added water concentration, RMSEP = 0.56% added water concentration and mean % relative error = 5.13% added water concentration, and RMECV = 0.36% added water concentration, RMSEP = 0.68% added water concentration and mean % relative error = 6.23%. RS analysis performed in quartz cuvettes enabled accurate water quantification with RMECV = 0.43% added water concentration, RMSEP = 0.67% added water concentration and mean % relative error = 6.75%. While the vibrational spectroscopic techniques studied have shown high performance in relation to reliable determination of water concentration, their accuracy is most likely related to their sensitivity to detect the LALP compounds in the NADES. For instance, whereas ATR-IR spectra display strong features from water, Levulinic Acid and L-Proline that contribute to the PLSR predictive models constructed, NIRS and RS spectra are respectively dominated by either water or LALP compounds, representing partial molecular information and moderate accuracy compared to ATR-IR. However, while ATR-IR instruments are common in chemistry and physics laboratories, making the technique readily transferable to water quantification in NADES, Raman spectroscopy offers promising potential for future development for in situ, sample withdrawal-free analysis for high throughput and online monitoring.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:27

Enthalten in:

Molecules (Basel, Switzerland) - 27(2022), 15 vom: 27. Juli

Sprache:

Englisch

Beteiligte Personen:

Elderderi, Suha [VerfasserIn]
Sacré, Pierre-Yves [VerfasserIn]
Wils, Laura [VerfasserIn]
Chourpa, Igor [VerfasserIn]
Elbashir, Abdalla A [VerfasserIn]
Hubert, Philippe [VerfasserIn]
Byrne, Hugh J [VerfasserIn]
Boudesocque-Delaye, Leslie [VerfasserIn]
Ziemons, Eric [VerfasserIn]
Bonnier, Franck [VerfasserIn]

Links:

Volltext

Themen:

059QF0KO0R
9DLQ4CIU6V
Attenuated total reflection infrared
Deep Eutectic Solvents
Journal Article
Label-free water quantification
Natural deep eutectic solvent
Near infrared spectroscopy
Partial least squares regression
Proline
Raman spectroscopy
Water

Anmerkungen:

Date Completed 15.08.2022

Date Revised 15.08.2022

published: Electronic

Citation Status MEDLINE

doi:

10.3390/molecules27154819

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM344755606