Silicone glue-based graphite ink incorporated on paper platform as an affordable approach to construct stable electrochemical sensors

This study describes the development of electrochemical paper-based analytical devices (ePADs) using carbon -based paste combining silicone glue and graphite powder. The ePADs were manufactured using the screen -printing technique, which consisted of depositing the conductive ink on a screencast on the paper surface. In addition, an alternative electrical connector was designed and 3D-printed to make the detection method cheaper, portable and reproducible. The morphological, structural, and electrochemical properties of the conductive material developed were investigated through scanning electron microscopy (SEM), Raman spectroscopy, elec-trochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) measurements. The ePADs combined with the alternative connector revealed high repeatability, reproducibility, and stable responses considering a well-known redox probe ([Fe(CN)6]4-/3-). In addition, the proposed ePAD provided a linear response for standard solutions of ascorbic acid (AA) in the concentration range between 0.1 and 2.0 mmol L-1. The achieved limit of detection was 4.0 mu mol L-1. As proof of applicability, the ePADs were evaluated for AA analysis in synthetic biofluids (blood plasma and urine), vitamin C tablets, and food (gelatine and orange juice) samples. The analytical parameters of the proposed device were compared with other reports in the literature and exhibited similar or even superior performance, highlighting its feasibility for sensing applications.

Automated summary

This study describes the development of electrochemical paper-based analytical devices (ePADs) using carbon-based paste combining silicone glue and graphite powder. The ePADs were manufactured using the screen-printing technique and an alternative electrical connector. The proposed ePADs showed high repeatability, reproducibility, and stable responses, and had linear response for ascorbic acid (AA) in the range of 0.1 to 2.0 mmol L-1, with a limit of detection of 4.0 mu mol L-1. The ePADs were evaluated for AA analysis in synthetic biofluids, vitamin C tablets, and food samples, and exhibited similar or even superior performance compared to other reports in the literature, showing its feasibility for sensing applications.