Thorough characterization of Greek honeys of different botanical origin using high resolution mass spectrometry (HRMS)

της παρούσας εργασίας ήταν η μελέτη και ο χαρακτηρισμός ελληνικών μελιών ποικίλων βοτανικών προελεύσεων. Για το σκοπό αυτό χρησιμοποιήθηκε η καινοτόμος αναλυτική τεχνική UHPLC-TIMS-TOF-MS. Ως τώρα η εν λόγω τεχνική δεν είχε εφαρμοστεί ποτέ για την μελέτη του φαινολικού κλάσματος των μελιών. Στην παρούσα, λοιπόν, έρευνα με άξονα την επιπλέον δυνατότητα διαχωρισμού που παρέχει το ion mobility προσδιορίστηκαν τα CCS values για μια σειρά προτύπων φαινολικών ενώσεων που υπάρχουν στο μέλι και έγινε επικύρωση της αναλυτικής μεθόδου προσδιορισμού των αντιοξειδωτικών με βάση τους αναλύτες αυτούς. Χρησιμοποιώντας την επικυρωμένη αυτήν αναλυτική μέθοδο δείγματα μελιού από οκτώ διαφορετικές ελληνικές βοτανικές ποικιλίες (πεύκο, έλατο, δρυς, θυμάρι, ερείκη, πορτοκάλι, καστανιά, κουμαριά) αναλύθηκαν και χαρακτηρίστηκαν ως προς τα αντιοξειδωτικά τους. Επιπλέον, η ανάλυση δειγμάτων τόσο με TIMS-ON όσο και με TIMS-OFF έκανε αντιληπτή την επιπλέον πληροφορία που παρέχει το TIMS καθώς συνεκλουώμενες ενώσεις που δεν διαχωρίζονταν στο TIMS-OFF προσδιορίζονται στο TIMS-ON λόγω των διαφορετικών τιμών των CCS values.The object of the present work was the study and characterization of Greek honeys of various botanical origins. The innovative analytical technique UHPLC-TIMS-TOF-MS was used for this purpose. Until now this technique has never been applied to the study of the phenolic fraction of honey. In the present study, focusing on the additional separation potential provided by ion mobility, the Collision Cross Section values (CCS values) for a number of standard phenolic compounds present in honey were determined and the analytical method for the determination of antioxidants based on these analyzers was validated. Using this validated analytical method, honey samples from eight different Greek botanical varieties (pine, fir, oak, thyme, heather, orange, chestnut, arbutus) were analyzed and characterized in terms of their antioxidants. In addition, sample analysis with both TIMS-ON and TIMS-OFF revealed the additional information provided by TIMS as non-TIMS-OFF compounds were identified in TIMS-ON due to different CCS values

Development of Analytical Strategies for the Determination of Olive Fruit Bioactive Compounds Using UPLC-HRMS and HPLC-DAD. Chemical Characterization of <i>Kolovi</i> Lesvos Variety as a Case Study

In this study, an overall survey regarding the determination of several bioactive compounds in olive fruit is presented. Two methodologies were developed, one UPLC-Q-TOF-MS method for the determination of olive fruit phenolic compounds and one HPLC-DAD methodology targeting the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, β, -γ, δ-) and squalene. Target and suspect screening workflows were developed for the thorough fingerprinting of the phenolic fraction of olives. Both methods were validated, presenting excellent performance characteristics, and can be used as reliable tools for the monitoring of bioactive compounds in olive fruit samples. The developed methodologies were utilized to chemical characterize the fruits of the Kolovi olive variety, originating from the island of Lesvos, North Aegean Region, Greece. Twenty-five phenolic compounds were identified and quantified in Kolovi olives with verbascoside, hydroxytyrosol, oleacein and oleomissional found in significantly high concentrations. Moreover, 12 new bioactive compounds were identified in the samples using an in-house suspect database. The results of pigments analysis suggested that Kolovi variety should be characterized as low pigmentation, while the tocopherol and squalene content was relatively high compared to other olive varieties. The characterization of Kolovi olive bioactive content highlighted the high nutritional and possible economic value of the Kolovi olive fruit

Development and validation of a high-throughput headspace solid-phase microextraction gas chromatography-mass spectrometry methodology for target and suspect determination of honey volatiles

The determination of volatile compounds is essential for the chemical characterisation of honey's aroma and its correlation to its sensory profile and botanical origin. The present study describes the development, optimization and validation of a new, simple and reliable method for the determination of volatile compounds in honey using headspace solid-phase microextraction combined with gas chromatography/mass spectrometry (HS-SPME-GC-MS). The optimization of the SPME conditions showed that the ratio of honey: water (2:1) and the incubation temperature (60 °C) are the most critical parameters. Gas chromatography was performed with medium polar Varian CP-Select 624 column and the experimental Retention Index for a number of compounds was determined as an additional identification feature for suspect analysis. The simultaneous use of four internal standards chlorobenzene, benzophenone, 2-pentanol and 4-methyl-2-pentanone and matrix matched calibration enhanced method accuracy achieving recoveries 73–114 % and repeatability ranging between 3.9 and 19 % relative standard deviations. Furthermore, the superiority of the HS-SPME to static head space technique was verified exhibiting four-to nine-fold higher sensitivity. Target and suspect screening were applied to 30 Greek honey samples and 53 volatile compounds belonging to different chemical classes, such as alkanes, aldehydes, ketones, alcohols, and esters were identified with quantified concentrations ranging between 3.1 μg kg−1 (Limonene) up to 20 mg kg−1 (Benzeneacetaldehyde). Among the new findings is the detection of Myrtenol in Greek pine honey and 2,3-butanediol in Greek oak honey. The developed analytical protocol can be a valuable tool in order to chemically characterize honey based on the volatile content