XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
307
T6: P–15
The structure and properties of mineral matter contained in solid fuels
studied using the XRD, IR, VSM and XPS spectroscopy methods
Magdalena Dudek
1
, Marek Skrzypkiewicz
2
, Maciej Sitarz
3
,
Antoni Żywczak
4
, and Robert Socha
5
1
AGH University of Science and Technology, Faculty of Energy and Fuels, Al. A. Mickiewicza 30,
30-059 Krakow, Poland
2
Insitute of Power Engineering, 01-330 Warsaw Augustówka 36, Poland
3
AGH University of Science and Technology, Faculty of Materials Science and Ceramic, Al. A.
Mickiewicza 30, 30-059 Krakow, Poland
4
AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology,
Al. A. Mickiewicza 30, 30-059 Krakow, Poland
5
PAN Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences,
Niezapominajek 8, Cracow, Poland
In direct carbon fuel cells (DCFCs), the chemical energy of coal can be directly converted
into electricity with a very high rate of efficiency. Development of a direct carbon fuel cell with
a solid oxide electrolyte (DC-SOFC) opens up new prospective ways of applying coal to the
production of electricity. It was previously found that upgraded coal containing up to 5 % ash
appears to be valuable solid fuel for DC-SOFC application. Coal samples included numerous
organic and inorganic (mineral matter) compounds. The impact of some inorganic compounds
may be positive. As a result of catalysis of the Boudouard reaction, an increase of CO and a
consequent improvement in DC-SOFC performance is observed within the temperature range
750‒850ºC. On the other hand, during DC-SOFC operation at increased temperatures, certain
undesirable chemical reactions may occur between impurities originating from mineral matter
and anode materials within the cell, which can lead to a considerable drop in performance
parameters and a shortened lifetime for the cell’s ceramic components. This research is focused
on investigating the impact of the chemical composition of mineral matter contained in solid
fuels on the performance of a DC-SOFC. The results of X-ray, IR, and XPS studies of mineral
matter originating from upgraded coals is reported Magnetic investigations were also carried
out on powdered coals. Magnetisation loops as well as magnetisation as a function of
temperature was measured in a VSM the 7407 type by Lake Shore. During the first heating,
magnetisation of samples was measured from 400 up to 1200 K (above magnetic
transformation) and then was cooled to 400 K (slightly below magnetic transformation). In order
to minimise the effect of thermal exposure during the first heating on the chemical
homogenization in the sample the temperature step for measurement was selected as 10 K. The
measurements were performed with a field of 1 T. Magnetisation loops were recorded during
heating from 400 up to 1200 K every 100 K with a maximum field of 15 kOe. The relationship
between the chemical composition of applied solid fuels and DC-SOFC power output is reported
and discussed.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
308
T6: P–16
Determination of antioxidant activity and polyphenols content in potato
chips by Raman and IR spectroscopy
Sylwester Mazurek
1
, Roman Szostak
1
, and Agnieszka Kita
2
1
Department of Chemistry, University of Wrocław,50-383 Wrocław, Poland
2
Department of Food Storage, Faculty of Food Science, Agricultural University, 50-375 Wrocław,
Poland, e-mail: sylwester.mazurek@chem.uni.wroc.pl
Polyphenols are secondary metabolites of plants having a diverse structure, physical
properties and molecular weight. They can be divided into several classes, including phenolic
acids, tannins and flavonoids. Antioxidant properties of polyphenols and their presence in
humans’ diet are responsible for the importance of these substances in the food-processing
industry. Colour-fleshed potatoes belong to a group of plants with the highest potential as a
source of polyphenols given their ease of cultivation. In potato tubers chlorogenic acid usually
accounts for 60 to 90 % of all phenolic compounds present. Several factors associated with the
manufacturing processes can influence the content of polyphenols in the final product. In the
case of chip production the temperature of frying and duration of the process have the strongest
impact.
3500
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0.0
0.2
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0.6
R
a
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it
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Wavenumber [cm
-1
]
100
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100
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FT Raman
Total polyphenols
R
2
=0.9911
P
re
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[
m
g
/g
]
Reference value [mg/g]
calibration
validation
Fig. 1. FT Raman spectra of potato chips obtained from colored-flesh potatoes and the prediction curve
for total polyphenols modeling on the basis of Raman data.
The application of vibrational spectroscopy for the determination of total polyphenols
content, antioxidant activity, color parameters and fat level in chips originated from yellow-,
red- and purple-fleshed potato varieties are presented. Raman, infrared (IR) and near-infrared
(NIR) spectra of the laboratory-prepared chips were collected. Combining spectral data with the
results of reference analyses, partial least squares regression models were built. To characterize
the elaborated models, the relative standard errors of prediction were calculated for calibration
and validation sets. In the case of total phenolics quantification by Raman/IR/NIR techniques,
these errors (%) amounted to 4.0/7.1/7.1 and 6.4/8.6/8.5 for calibration and validation samples,
respectively, whereas they were equal to 4.9/7.7/4.8 and 6.6/8.3/6.8 for antioxidant activity. The
obtained results demonstrate that both infrared and Raman spectroscopy can effectively replace
commonly used extraction methods and that Raman spectroscopy has the highest potential to be
adopted for the online potato-derived product analysis.
Keywords: colored potatoes; chips; polyphenols; antioxidant activity; quantification, vibrational spectroscopy
Acknowledgment
Research supported by Wrocław Centre of Biotechnology, program The Leading National Research Centre
(KNOW) for years 2014–2018.
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