Selective detection of liposoluble vitamins using an organic electrochemical transistor

Accurate quantification of vitamins content is essential in food analysis, with direct impact on the quality of our diet and, therefore, on our health. Current research interest is devoted to the design of robust and versatile devices able to perform real-time analyses that do not strictly rely on laboratory facilities. Here, we report the first organic electrochemical transistor (OECT) based sensor working in organic environment for the detection of a fat-soluble vitamin (Vitamin A). The OECT behaviour in organic solvents was thoroughly characterized and its structure was optimised allowing both potentiostatic and potentiodynamic detections. On one hand, the potentiostatic approach provided a gain of 100 and the detection limit was as low as 115 nM, but it did not address selectivity issues. On the other hand, the potentiodynamic approach showed a higher detection limit, but allowed the selective detection of Vitamin A in the presence of α-Tocopherol. Analyses of randomized solutions revealed that a pre-calibrated sensor can estimate Vitamin A concentration with a 3% error. Moreover, the robustness of our sensor was demonstrated by analysing commercial food fortifiers without any sample pre-treatment.