Comprehensive two-dimensional gas chromatography (GC×GC) is the most effective multidimensional separation technique for in-depth characterization of complex fractions of volatiles (VOCs) in food. It enables highly informative fingerprinting and, if combined with Mass Spectrometry, it has the intrinsic potential to provide a detailed profiling giving access to the higher level of information encrypted in VOCs patterns: samples origin, technological signature, sensory profile [1,2]. Time of Flight Mass Spectrometry (TOFMS), featuring tandem hard and soft electron ionization, adds a further dimension to the analysis thereby enabling more confident identifications but also new challenges for the data processing. Consecutive alternate switching between hard (70 eV) and soft ionization (10-16 eV) provides complementary MS signatures (about each component and for each 2D pattern) increasing the dimensionality of the analysis and offering new possibilities for results cross-validation. However, suitable pattern recognition procedures (template matching and transformation algorithms) as well as correction/normalization of MS responses have to be considered to extend method fingerprinting capabilities over a wide-time frame. This study focuses on the complex volatile fraction from Extra Virgin Olive (EVO) oils selected within the Italian Ager project “Violin” [3] because of their peculiar sensory characteristics and/ or coherent with European Quality Labeling (Protected Denomination of Origin). VOCs are sampled by Head Space Solid Phase Microextraction (HS-SPME) with different sorption/ adsorption polymers, separation is on a polar × semi-polar column combination and detection by tandem hard (70 eV) and soft (12 eV) electron ionization TOFMS. 2D patterns from EVO oils, acquired over a one-year time frame and under similar (but not identical) chromatographic conditions, are evaluated for 2D peak pattern shifts (targeted and untargeted peak-region features) and response fluctuations. Data transformation and normalization strategies are discussed in view of a fingerprinting method validation for large scale studies

GC×GC- tandem ionization-TOFMS with combined untargeted and targeted (UT) fingerprinting of volatiles from extra virgin olive oil: challenges for data aligment and response normalization

STILO, FEDERICO;Erica Liberto;Cecilia Cagliero;Patrizia Rubiolo;Barbara Sgorbini;Carlo Bicchi;Chiara Cordero
2018

Abstract

Comprehensive two-dimensional gas chromatography (GC×GC) is the most effective multidimensional separation technique for in-depth characterization of complex fractions of volatiles (VOCs) in food. It enables highly informative fingerprinting and, if combined with Mass Spectrometry, it has the intrinsic potential to provide a detailed profiling giving access to the higher level of information encrypted in VOCs patterns: samples origin, technological signature, sensory profile [1,2]. Time of Flight Mass Spectrometry (TOFMS), featuring tandem hard and soft electron ionization, adds a further dimension to the analysis thereby enabling more confident identifications but also new challenges for the data processing. Consecutive alternate switching between hard (70 eV) and soft ionization (10-16 eV) provides complementary MS signatures (about each component and for each 2D pattern) increasing the dimensionality of the analysis and offering new possibilities for results cross-validation. However, suitable pattern recognition procedures (template matching and transformation algorithms) as well as correction/normalization of MS responses have to be considered to extend method fingerprinting capabilities over a wide-time frame. This study focuses on the complex volatile fraction from Extra Virgin Olive (EVO) oils selected within the Italian Ager project “Violin” [3] because of their peculiar sensory characteristics and/ or coherent with European Quality Labeling (Protected Denomination of Origin). VOCs are sampled by Head Space Solid Phase Microextraction (HS-SPME) with different sorption/ adsorption polymers, separation is on a polar × semi-polar column combination and detection by tandem hard (70 eV) and soft (12 eV) electron ionization TOFMS. 2D patterns from EVO oils, acquired over a one-year time frame and under similar (but not identical) chromatographic conditions, are evaluated for 2D peak pattern shifts (targeted and untargeted peak-region features) and response fluctuations. Data transformation and normalization strategies are discussed in view of a fingerprinting method validation for large scale studies
42nd International Symposium on Capillary Chromatography and 15th GC×GC Symposium
Riva del Garda, Italy
May 13 – 18, 2018
42nd International Symposium on Capillary Chromatography and 15th GC×GC Symposium Astract Book
L. Mondello and P. Dugo
352
352
978-88-941816-1-6
Federico Stilo, Erica Liberto, Cecilia Cagliero, Patrizia Rubiolo, Barbara Sgorbini, Stephen E. Reichenbach, Qingping Tao, Carlo Bicchi, Chiara Cordero
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1670778
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