Carbon-Black Integrated Polylactic Acid Electrochemical Sensor for Chloramphenicol Determination in Milk and Water Samples

Abstract

Extrusion-based three-dimensional (3D) printing is a promising technology for the construction of electrochemical devices and some features can be highlighted such as low-cost, versatility, large-scale production, fast prototyping in varied designs and availability of conductive filaments. Herein, we show the detection of chloramphenicol (CAP) in milk and tap water samples using carbon-black integrated polylactic acid (CB/PLA) electrodes fabricated by combining a 3D pen and 3D-printed substrates. The electrode surface activated in basic medium provided a considerable improvement of CAP response (12-fold) due to the removal of PLA and consequent higher exposure of conductive sites. Differential-pulse voltammetric measurements exploring the reduction of the nitro group of CAP at −0.45 V (vs. Ag∣AgCl∣KCl(sat.)) were performed. A wide linear range (10–331 μmol L−1, r = 0.998) with a detection limit of 0.98 μmol L−1 was obtained with a precision of 5.1% (n = 10). Tap water and milk samples were spiked with known amounts of CAP and analyzed by the standard-addition method. Recovery values between 88–93% demonstrated that sample matrix did not interfere on the CAP determination. Therefore, this work shows a promising tool for low-cost construction of electrodes for CAP detection in food and environmental samples which can be extended to other antibiotics.