Electrochemical Screening of Biomarkers in Chemotype Mexican Oregano Oils on Single-Walled Carbon Nanotubes Screen-Printed Electrodes

An electrochemical screening for the determination of total biomarkers (thymol and carvacrol) of Lippia graveolens using single-walled carbon nanotubes screen-printed electrodes (SWCNT-SPEs) is proposed. The suitability of the approach was demonstrated using GC-MS by the analysis of selected Mexican oregano essential oil chemotypes. The analytical performance was excellent in terms of inter-droplet precision (RSD≤6 %), sensitivity and linearity. An electrochemical index of biomarkers is proposed for fast assessment of oregano quality using just 50 µL of the sample. The route here proposed constitutes a very convenient screening tool in decentralized analysis because of the simplicity, disposability and easy-to-use by non-specialist user.