Thermal Desorption-Electrospray Ionization/Mass Spectrometry (TD-ESI/MS) Combined with Multivariate Analysis for Rapid Identification of Cooking Oils

Autor: Ting-Hao Chang, 張庭晧
Rok vydání: 2015
Druh dokumentu: 學位論文 ; thesis
Popis: 103
Recently, oil mixtures and recycled oils have also been added to cooking oils, deceiving consumers and endangering their health, so that elucidation of oil components is of increasing importance. Oil mixtures and recycled oils have different triglyceride (TG) compositions compared to normal oils. Traditional TG detection methods use gas chromatography-flame ionization detector (GC-FID) after saponification and methyl esterification, which is tedious and time-consuming. Compared to GC, ambient mass spectrometry (AMS) significantly reduces analytical times because it avoids complex sample pretreatment. In this study, an AMS technique known as thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) combined with multivariate analysis was used to rapidly classify various cooking oils. The ambient TD-ESI source consisted of (1) a sampling probe to obtain analytes from solid or liquid samples, (2) a heated oven for thermally desorbing analytes from the sampling probe, and (3) an ESI source for post-ionizing analytes via interactions with reactive species produced by ESI. The mass spectra obtained from TD-ESI/MS were then analyzed using multivariate analysis software. This study is divided into four parts. First, we find optimum conditions of cooking oil analysis using TD-ESI/MS. The second is method validation. We verify the correctness of cooking oil analysis using TD-ESI/MS via ESI/MS. Third, we used TD-ESI/MS combined with multivariate analysis to rapidly classify various cooking oils and identify cooking oils in food products such as lunchboxes, fries, potato chips, barbeque sauces, instant noodles, cookies, and bread. TD-ESI/MS was also successfully applied to distinguish components in different oil mixtures (i.e. lard, soybean oil, palm oil, and olive oil). Finally, TD-ESI/MS was used to monitor cooking oil at heating and record the decompose of cooking oil in high temperature.
Databáze: Networked Digital Library of Theses & Dissertations
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