Simple and Inexpensive Electrochemical Platform Based on Novel Homemade Carbon Ink and its Analytical Application for Determination of Nitrite

Abstract

In this work we present the development of a simple handmade approach for the easy fabrication of three‐electrode electrochemical devices based on newly in‐house developed carbon ink composed of graphite powder and polystyrene. Different proportions of graphite/polystyrene were investigated for the optimization of the ink. The counter and reference electrodes were produced using commercial carbon ink and silver glue. Scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to investigate the morphology and the electrochemical properties of the sensor. The results showed that the electroactive area of the optimized working electrode was ca. 2.35 times larger than its geometric area. The RSD values obtained for repeatability and reproducibility were 0.20% and 2.78%, respectively, which suggest no significant variation on the electrodes fabricated. The analytical feasibility of the electrode was tested through its application for the determination of nitrite in drinking water. The quantifications were successfully performed at levels below the maximum contaminant level established for nitrite. A limit of detection of 1.42 × 10−6 mol L−1 and recoveries of ca. 103 % were achieved. The results were validated using ion‐chromatography technique with good agreement. The performance of the unmodified sensor proposed here on nitrite determination was better than some recently reported modified electrodes obtained through complex procedures.

Design of novel, simple, and inexpensive 3D printing‐based miniaturized electrochemical platform containing embedded disposable detector for analytical applications

“…A and B, the surface of the electrochemical sensor presented itself as slightly rough and irregular, which is typically observed for carbon‐based electrodes. The defective and wrinkled morphology of the sensor may benefit the sensitivity aiming analytical applications .…”

“…The PDMS structures used here were produced according to a well‐established protocol described elsewhere . Briefly, PDMS monomer and its curing agent were mixed at 9:1 ratio, degassed under vacuum, and then deposited over the 3D printed mold.…”

“…The PDMS structures used here were produced according to a well-established protocol described elsewhere [30][31][32].…”

“…2A and B, the surface of the electrochemical sensor presented itself as slightly rough and irregular, which is typically observed for carbon-based electrodes. The defective and wrinkled morphology of the sensor may benefit the sensitivity aiming analytical applications [20,32]. The electrochemical activity of the proposed platform was investigated towards the benchmark redox system ferrocyanide/ferricyanide in an aqueous media composed of potassium chloride [32].…”

“…The defective and wrinkled morphology of the sensor may benefit the sensitivity aiming analytical applications [20,32]. The electrochemical activity of the proposed platform was investigated towards the benchmark redox system ferrocyanide/ferricyanide in an aqueous media composed of potassium chloride [32]. The effect of the scan rate on the electrochemical response of 1 mM each of K 3 (FeCN) 6 /K 4 (FeCN) 6 in 0.5 M KCl was evaluated through CV, such as displayed in Supporting Information Fig.…”