Tag Archives: hidden peaks

1645-1651 P. Laurson, H. Kaldmäe, A. Kikas and U. Mäeorg
Detection of changes in the water, blackcurrant- and raspberry juice infrared spectrum in the range 2,500−4,000 cm-1
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Detection of changes in the water, blackcurrant- and raspberry juice infrared spectrum in the range 2,500−4,000 cm-1

P. Laurson¹*, H. Kaldmäe², A. Kikas² and U. Mäeorg¹

¹Faculty of Science and Technology, Institute of Chemistry, University of Tartu, Ravila 14a, EE50411 Tartu, Estonia
²Polli Horticultural Research Centre PlantValor of the Institute of Agricultural and Environmental Sciences, the Estonian University of Life Sciences, EE69104 Karksi-Nuia, Estonia
*Correspondence: peeter.laurson@ut.ee

Abstract:

This research was conducted to develop a method for the establishment of changes in absorbance that occurs in the OH stretching vibration region 2,500−4,000 cm-1 of FT-IR transmission spectra of water and juices. With the methodology described in this paper, a signal-to-noise ratio was obtained, which allows to measure the reproducibly of the FT-IR transmission spectra of water and juices. The article points out some important aspects of how the spectra of ultrapure water, blackcurrant- (Ribes nigrum L.) and raspberry (Rubus idaeus) juices were measured in the OH stretching vibration region 2,500−4,000 cm-1. The graphical comparison of raw spectra illustrates that the differences which occur in the spectra of water and juices are hard to differentiate. For the clear distinction of differences in spectra, there are four hidden peaks identified in the analysis of spectra by using the deconvolution method. There are clear differences identified in the comparison of percentages of the hidden peaks of spectra in the areas of ultrapure water, blackcurrant and raspberry juice. Repeated measurements and analysis of spectra provide reproducible results. It was established that the developed method can be used for the detection of changes in the FT-IR transmission spectra of water, juices and aqueous solutions with low molar concentrations of additives. The distinction of changes in the spectra is a precondition for research of the clustered structures of water

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