Disposable electrochemical sensors by using recyclable materials are an interesting alternative to produce electrochemical sensors with an extreme low cost. In addition, the screen-printing technique has been widely used to propose electrochemical devices with new conductive inks for different applications. In this context, we develop a disposable eco-friend sensor with relative cost low and easy production. A conductive ink was produced with nail polish and graphite powder. As a sensor substrate, we reuse polyethylene terephthalate (PET) from drink bottles. The characterizations of the proposed electrode were performed by using scanning electron microscopy, infrared microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The determination of hydroquinone (HQ), epinephrine (EP) and serotonin (5-HT) were chosen as proof of concept. Using square wave voltammetry, for HQ, the PET sensor showed a linear response in the concentration range of 5.0 to 100 mu mol L-1 with a detection limit (LOD) of 0.01 mu mol L-1. Differential pulse voltammetry was applied for EP and 5-HT detection, and the proposed electrode presented linear response in the range of 5.0 to 100 mu mol L-1 and 1.0 to 50 mu mol L-1 and LODs of 0.3 and 0.1 mu mol L-1 for EP and 5-HT, respectively. Then, the disposable PET sensor was applied in the determination of HQ in environmental and pharmaceutical samples and, EP and 5-HT in biological samples. The proposed electrode is simple to prepare and can be easily used for electrochemical sensing and biosensing.