Conductive Polypropylene Additive Manufacturing Feedstock: Application to Aqueous Electroanalysis and Unlocking Nonaqueous Electrochemistry and Electrosynthesis

Additive manufacturing electrochemistry is an ever-expanding field; however, it is limited to aqueous environments due to the conductive filaments currently available. Herein, the production of a conductive poly(propylene) filament, which unlocks the door to organic electrochemistry and electrosynthesis, is reported. A filament with 40 wt % carbon black possessed enhanced thermal stability, excellent low-temperature flexibility, and high conductivity. The filament produced highly reproducible additive manufactured electrodes that were electrochemically characterized, showing a k0 of 2.00 ± 0.04 × 10-3 cm s-1. This material was then applied to three separate electrochemical applications. First, the electroanalytical sensing of colchicine within environmental waters, where a limit of detection of 10 nM was achieved before being applied to tap, bottled, and river water. Second, the electrodes were stable in organic solvents for 100 cyclic voltammograms and 15 days. Finally, these were applied toward an electrosynthetic reaction of chlorpromazine, where the electrodes were stable for 24-h experiments, outperforming a glassy carbon electrode, and were able to be reused while maintaining a good electrochemical performance. This material can revolutionize the field of additive manufacturing electrochemistry and expand research into a variety of new fields.

Fabrication of a simple 3D-printed microfluidic device with embedded electrochemiluminescence detection for rapid determination of sibutramine in dietary supplements

The design and fabrication of a simple 3D-printed platform with embedded electrochemiluminescence (ECL) detection for sibutramine determination is described. The microfluidic platform was fabricated by the fused deposition 3D-printing technique with polylactic acid filament, facilitated by computer-aided design (CAD). A three-electrode system was integrated into the device using graphene carbon paste as a working electrode, Ag/AgCl wire as a reference, and a graphite rod as a counter electrode. A further modification was carried out by applying bimetallic Au-Pt nanoparticle-supported multi-walled carbon nanotubes (MWCNT-Au-Pt) on the working electrode surface to enhance the electrocatalytic performance by exploiting the unique properties of nanomaterials. The analytical feasibility of the CAD-ECL sensor was tested through its application for the determination of sibutramine in dietary supplements. Under the optimized conditions, based on the enhancing effect of luminol emission, the device exhibited a linear calibration curve of the logarithmic sibutramine concentration versus ECL intensity in the range 5 × 10^-3 to 1 ng mL^-1. The limit of detection was 3 pg mL^-1 with a relative standard deviation of 1.7% (n = 15). The 3D-printed prototype can be successfully applied to a small-scale analysis in a simple and cost-effective approach.

Graphene oxide–porphyrin composite nanostructure included electrochemical sensor for catechol detection

A novel composite nanostructure (GO–Por) has been prepared via ultrasonication and exhibited enhanced electrocatalytic activity towards catechol oxidation.

A polyoxy group branched diazo dye as an alternative material for the fabrication of an electrochemical epinephrine sensor

A polyoxy group attached diazo dye on an electrode surface improved the voltammetric response of epinephrine.