Differentiation of mint species and varieties through headspace analysis based on polymer-modified piezoelectric quartz crystal sensors

Abstract

Mint plants have been traditionally used in flavors, fragrances, and medicines throughout the world. Polymer-modified piezoelectric quartz crystal sensor through headspace analysis was used to discriminate the six varieties of mint plant, namely: Chocolate mint (Mentha x piperita 'Chocolate'), Java mint (Mentha arvensis var. javanica), Water mint (Mentha aquatica), Peppermint (Mentha x piperita), Lemon mint (Mentha x piperita f. citrata) and Japanese peppermint (Mentha arvensis var. piperascens). Five quartz crystals were coated separately with the following polymers: polyethylene glycol (PEG), polystyrene (PS), polyvinyl chloride (PVC), cyanoacrylate (CA) and polydimethylsiloxane (PDMS) on both sides of the quartz crystal. The sample of mint leaves was placed in a sample chamber and were studied using one polymer-coated sensor at a time. The headspace vapors from the incubated sample interact with the polymer-coated sensor causing a frequency shift. The data collected for each plant for the five sensors were analyzed using pattern recognition methods.