Rapid pretreatment-free evaluation of antioxidant capacity in extra virgin olive oil using a laser-nanodecorated electrochemical lab-on-strip.

[Display omitted] • A lab-on-strip device for direct evaluation antioxidant capacity of EVOO is proposed. • The device is composed of a laser nanodecorated sensor and a paper sampler. • The device is manufactured with office-grade materials and accessible instruments. • The device is portable and encloses all the analysis steps. • EVOO analysis occurs in 2 min and needs 4 µL of not pretreated sample. An electroanalytical lab-on-a-strip device for the direct extra-virgin olive oil (EVOO) antioxidant capacity evaluation is proposed. The lab-made device is composed of a CO 2 laser nanodecorated sensor combined with a cutter-plotter molded paper-strip designed for EVOOs sampling and extraction. Satisfactory performance towards the most representative o-diphenols of EVOOs i.e., hydroxytyrosol (HY) and oleuropein (OL) were achieved; good sensitivity (LOD HY = 2 µM; LOD OL = 0.6 µM), extended linear ranges (HY: 10–250 µM; OL: 2.5–50 µM) and outstanding reproducibility (RSD < 5%, n = 3) were obtained in rectified oil. The device was challenged for the extraction-free analysis of 15 different EVOO samples, with satisfactory recoveries (90–94%; RSD < 5%, n = 3) and correlation with classical photometric assays (r ≥ 0.91). The proposed device includes all analysis steps, needs 4 µL of sample, and returns reliable results in 2 min, resulting portable and usable with a smartphone. [ABSTRACT FROM AUTHOR]