In the present article the development of a paper-based amperometric sensor for the determination of glucose and of the total carbohydrates is described. The motivation of the study lies in the necessity of novel low cost and fast methods for the determination of sugars in foodstuff; the commonly used procedures, in fact, often suffer from inaccuracy. To this aim, paper-based electrodes have been fabricated through the deposition of an electrically conductive ink based on Cu nanoparticles, graphite and polystyrene. In order to gain highest oxidation currents for glucose, i.e. to increase the sensitivity of the sensor, the composition of the ink has been optimised through a suitable experimental design. The performance of the paper-based system has been estimated in glucose, 0.1 M KOH solution. The estimated concentration value calculated from the calibration curve is ca. 10.4 mM (0.6 mM standard deviation) when a probe solution containing 10.1 mM glucose is used. In addition, the effectiveness of the system has been verified in real matrices, i.e. soft drinks: calibration curves lead to accurate estimation of the total carbohydrates concentration. On the basis of a suitable t-test, the probability of being wrong in rejecting the proper null hypothesis is lower than 1%.
