High-throughput chromatographic fingerprinting of Extra Virgin Olive Oil volatiles by GC×GC-MS/FID and differential flow modulation

Introduction Comprehensive two-dimensional gas chromatography combines the information power of detailed profiling and effective fingerprinting by producing samples unique 2D patterns helpful for discrimination and classification purposes. The possibility to routinely perform highly informative fingerprinting/profiling on large sample set is attractive, but requires analytical platforms with low operational costs, simpler laboratory management and robust and repeatable performances over time. Methods This study explores the feasibility of transferring a fingerprinting method for Extra Virgin Olive oils (EVOOs) volatiles from thermal modulated (TM) GC×GC-MS to a differential flow modulated (FM) platform. The principles of method translation are adopted to effectively transfer the application from TM to FM by preserving analytes elution order, 1D resolution and 2D pattern coherence. Results The translation of chromatographic parameters as columns dimensions, carrier gas conditions and temperature programming affords effective application transfer by preserving analytes elution order and original method resolution. Translated methods enable effective chromatographic fingerprinting based on template matching with performances comparable with TM platforms and with limited analyst’s supervision. Main drawbacks of FM-GC×GC are due to the lack of band compression in space, that impacts on method sensitivity and separation power. Original TM templates of reliable peaks from EVOOs volatiles, when applied to 2D pattern obtained in translated conditions, achieve a 33% of positive matches. However, when targeted analytes are considered (i.e. known markers of EVOOs quality) the positive matches are higher and about 50% while for potent odorant (both C5 and C6 aldehydes/alcohols and the off-flavor characteristics compounds) the coverage is of about 80%. Conclusions Experimental results on guided method translation, confirm that EVOOs volatiles fingerprinting is feasible by FM GC×GC by preserving 2D patterns information potential and providing mutually coherent sample clustering. The information potential of samples’ fingerprints based on known markers is also partially preserved, despite the loss of sensitivity, and 16 over 20 key-aroma compounds are successfully detected.