Palm-Leaf Manuscripts - FTIR Data

Data

This dataset was created in the context of the Research Field F (RFF02) and the Palm-Leaf Manuscript Profiling Initiative (PLMPI). The data of Palm-leaf manuscripts was recorded with FTIR spectroscopy (DRIFTS, EXOSCAN) from C. Colini, L. F. Voges and N. Horn in the years 2021-2023.

Please refer to the RDR-Entry for further information (where this page is hosted) and to the published research paper.

DRIFTS single Spectra

The pure spectra can be viewed here. There is no preprocessing or other manipulation added.

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Preprocessed spectra per Manuscript

For better comparison the spectra are normalised (SNV) and reduced to the spectral range from 800–3840 cm\(^{-1}\). Also, only every 5th data point is displayed for better performance.

Manuscript

Country

India Indonesia Myanmar Sri Lanka

Species

Borassus flabellifer

Corypha umbraculifera

Data Analysis

Data analysis based on the processed FTIR spectra. The preprocessing of spectra included reducing the spectral range from 800 to 1900 and 2400 to 3840 cm\(^{-1}\). Hence the area from 1900 to 2400 cm\(^{-1}\), which can show peaks from carbon dioxide of the ambient air, was skipped in the analysis. Furthermore, preprocessing included smoothing with Savitzky–Golay filter and forming the first derivative using prospectr package. Standard Normal Variate (SNV) method was applied with prospectr package for normalisation and scatter correction. Principal component analysis (PCA) was carried out with the prcomp() function (non-scaled, centered). Not all spectra were selected in the analysis workflow (e.g. outliers or measurements on stains). Therefore, the respective number of measurements can be different from the “Data” page.

In the following the PCA (Principal Component Analysis) is shown. The species is very prominent regarding the variance in the data. Therefore the manuscripts of the two species is shown separately. For each further differences e.g. from the country of origin is then more prominent.

PCA of all Spectra

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PCA of Borassus flabellifer

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PCA of Corypha umbraculifera

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Information

The here presented analysis and data should be used as a quick overview and addition to the published article and data. Some of the data shown is simplified and may not reflect reality.

Contact Information:
Lucas F. Voges
lucas.voges@uni-hamburg.de
CSMC - Universität Hamburg

June 2024

FTIR instrument

4100 Exoscan FTIR spectrometer (Agilent Technologies) was used in Diffuse Reflectance mode (DRIFTS). The spectrometer is equipped with a ZnSe beam splitter, a Michelson interferometer and a thermoelectrically cooled dTGS detector. It has a spectral range of 4000–650 cm\(^{-1}\) and a spectral resolution of 4 cm\(^{-1}\). A gold reference cap was used for background calibration. 256 scans were collected in one measurement. Measurements were taken on unwritten and written parts of the manuscripts.

Interactive visualisation done with Quarto and R

• R version 4.2.2 (2022-10-31)
• Quarto version 1.4.553
• packages: crosstalk 1.2.1, DT 0.33, ggplot2 3.5.1, htmlwidgets 1.6.4, leaflet 2.2.2, plotly 4.10.4, reshape2 1.4.4