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Transformations to reduce the effect of particle size in mid-infrared spectra of biomass


Fourier Transform InfraRed spectroscopy (FTIR) is a very powerful technique in the characterization of the chemical composition of biomass and its modifications occurring during thermochemical and chemical pretreatments. However, methods development are necessary to generate reproducible signals that can be used in combination with multivariate techniques (as principal components analysis, PCA) to extract meaningful information on biomass composition and bonds cleave. Particle size is a great source of spectra variability in FTIR of biomass. The FTIR signal for an array of particle sizes (2 – 0.075 mm) was evaluated for hardwood and switchgrass, determining 0.5 mm renders higher intensity and spectral reproducibility for both FTIR sampling techniques investigated (ATR and HTS-XT). Furthermore, the suitability of different signal processing approaches to decrease particle size variability of spectral signal were tested (signal normalization, derivation, and combinations). Normalization showed the highest contribution to enhance ATR spectral reproducibility of both biomass, as statistically shown by the 5-fold decrease of the ratio of signal variance with magnitude of spectral features (VM ratio) with respect to unprocessed signal. Spectral signal analysis in combination with multivariate statistics (PCA, principal component analysis) was used to extract information about the chemical differences between hardwood and switchgrass. The agreement of the biomass composition findings yielded by FTIR-PCA and literature wet chemistry results (acid hydrolysis) contributed to corroborate that FTIR combined with PCA is a clean, quick, efficient, and versatile technique with potential to analyze and characterize biomass composition.

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Publication details

The article was received on 20 Jun 2018, accepted on 27 Aug 2018 and first published on 10 Sep 2018

Article type: Paper
DOI: 10.1039/C8AN01137K
Citation: Analyst, 2018, Accepted Manuscript
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    Transformations to reduce the effect of particle size in mid-infrared spectra of biomass

    B. Cantero-Tubilla and L. Walker, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C8AN01137K

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