Home > Archive > No. 3–4 (195–196) 2024 > 100–125
Geology & Geochemistry of Combustible Minerals No. 3–4 (195–196) 2024, 100–125
https://doi.org/10.15407/ggcm2024.195-196.100
Yurii KHOKHA1, Myroslava YAKOVENKO2
Institute of Geology and Geochemistry of Combustible Minerals of National Academy of Sciences of Ukraine, Lviv, Ukraine, e-mail: 1khoha_yury@ukr.net; 2myroslavakoshil@ukr.net
Abstract
The article discusses theoretical and practical aspects of the use of near infrared (NIR) spectroscopy combined with chemometrics for express analysis of peat. Near infrared spectroscopy provides a significant amount of information about complex organic systems, including irregular polymers such as peat. Compared to classical analytical methods, NIR spectrometry allows analysis without complex sample preparation with analysis time measured in minutes. Since the results represent the intensity of radiation reflection in the overtone range of fundamental frequencies, their processing requires the use of special mathematical and statistical methods. The use of the Chemoface software package modules (PLS method) for quantitative analysis of the technical and chemical properties of peat based on NIR spectroscopy data has demonstrated the possibility of obtaining calibration models that allow for the quick and reliable analysis of this raw material, including in field conditions. The conducted studies have shown that using a spectrometer that analyzes reflected (absorbed) radiation in the near-infrared spectrum and based on the averaged spectral characteristics of the reflected (absorbed) radiation and using chemometric software, it is possible to calculate the chemical and technological characteristics of peat. The analysis procedure consists of the following stages: selection of a sample representing the entire batch of raw materials; irradiation of the sample with radiation containing a significant proportion of energy in the near-infrared spectrum; analysis with a detector of reflected (absorbed) radiation and construction of an integral spectral characteristic of the sample; compilation of a calibration model using chemometric software; processing of the obtained spectrum using chemometric software with subsequent calculation of the qualitative and quantitative characteristics of the raw materials. The proposed method (express analysis) for rapid determination of qualitative and quantitative characteristics of fossil carbon raw materials of organic origin, namely lowland and highland peat of various degrees of decomposition, can be used to establish its compliance with current norms, standards and technical conditions for moisture content, ash (inorganic) residue content and acidity (pH).
Keywords
near-infrared reflectance (NIR) spectroscopy, peat analysis, predictive models, multivariate analysis, Partial Least Squares Regression (PLS), pre-treatments effect
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