A modified commercial gas chromatograph for the continuous monitoring of the thermal degradation of sunflower oil and off-line solid phase extraction gas-chromatography-mass spectrometry characterization of released volatiles.
A homemade flow cell attached to a commercial Gas Chromatograph equipped with a Flame Ionization Detector (FID) has been designed for the continuous monitoring of volatile compounds released during heating edible oils. Analytical parameters such as mass of sample, temperature and flow rates have been optimized and the obtained results have been compared with the corresponding thermographs from standard TG systems. Results show that under optimum conditions, the profiles of volatiles released upon heating are comparable to the profiles of TG curves, suggesting that the FID based system could be an alternative to TGA. Additionally, volatiles have been retained in a Lichrolut EN(®) resin, eluted and analyzed by Gas Chromatography-Mass Spectrometry. In this case, forty five compounds have been identified (acids, alcohols, alkanes, aldehydes, ketones and furans) and compared with the FID signals, working both in air or nitrogen atmosphere. It has been concluded that the oxidative thermal degradation is prevented in the presence of a nitrogen atmosphere.
Laboratory for Flavour Analysis and Enology (LAAE), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain.
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Ontañon
Analytical Biosensors Group (GBA), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain.
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Sanz
Laboratory for Flavour Analysis and Enology (LAAE), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain. Electronic address: escudero@unizar.es.
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Escudero
Analytical Biosensors Group (GBA), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain.
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de Marcos
Laboratory for Flavour Analysis and Enology (LAAE), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain.
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Ferreira
Analytical Biosensors Group (GBA), Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E50009 Zaragoza, Spain.
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Galbán
D002849:Chromatography, Gas / Q000379:methods; D005410:Flame Ionization / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006358:Hot Temperature; D010938:Plant Oils / Q000032:analysis* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods*; D000074242:Sunflower Oil; D013816:Thermodynamics; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000302:isolation & purification
D010938:Plant Oils; D000074242:Sunflower Oil; D055549:Volatile Organic Compounds
FID; SPE–GC–MS; Sunflower oil; Thermal degradation; Thermogravimetry