Improving the performance and versatility of microfluidic thread electroanalytical devices by automated injection with electronic pipettes: a new and powerful 3D-printed analytical platform.

Microfluidic cotton thread-based electroanalytical devices (μTEDs) are analytical systems with attractive features such as spontaneous passive flow, low cost, minimal waste production, and good sensitivity. Currently, sample injection in µTEDs is performed by hand using manual micropipettes, which have drawbacks such as inconstant speed and position, dependence of skilled analysts, and need of physical effort of operator during prolonged times, leading to poor reproducibility and risk of strain injury. As an alternative to these inconveniences, we propose, for the first time, the use of electronic micropipettes to carry out automated injections in µTEDs.

Exploring the coating of 3D-printed insulating substrates with conductive composites: a simple, cheap and versatile strategy to prepare customized high-performance electrochemical sensors.

The development of 3D-printed electrochemical sensors by fused deposition modeling (FDM) has been increasing exponentially in the last five years. In this context, commercial conductive filaments composed of a blend of carbon particles (, graphene or carbon black (CB)) and insulating thermoplastic polymers (, polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS)) have been widely used for electrode fabrication. However, such materials may be expensive and the electrodes when used "as-printed" exhibit poor electrochemical performance as a function of the low content of conductive particles in the composition (∼10 to 20 wt%), which requires one or more post-treatment steps ( polishing, chemical, electrochemical, and photochemical) to reach good electrochemical performance.

Arbuscular mycorrhizal fungi activity in the rhizosphere of tree seedlings subjected to residual herbicides.

Trees occurring on the margins of agricultural areas can mitigate damage from residual herbicides. Rhizospheric microbial activity associated with trees is one of the main remedial capacity indicators. The objective of this study was to evaluate the rhizospheric microbiological activity in tree species subjected to the herbicides atrazine and sulfentrazone via the rhizosphere.

Multi sensor compatible 3D-printed electrochemical cell for voltammetric drug screening.

3D printing is a hot topic in electroanalytical chemistry, allowing the construction of custom cells and sensors at affordable prices. In this work, we describe a novel small and practical 3D-printed electrochemical cell. The cell's body, manufactured in ABS on a 3D printer, is composed by three parts easily screwed: solution vessel, stick and cover with two embedded 3D-pen-printed carbon black-polylactic acid (CB-PLA) electrodes (counter and pseudo-reference).

Cloud-point extraction associated with voltammetry: preconcentration and elimination of the sample matrix for trace determination of methyl parathion in honey.

This work presents the association of cloud point extraction (CPE) and electroanalysis for the selective and sensitive determination of methyl parathion (MP) in honey. The CPE step provided the pre-concentration of MP from a complex sample, in which the optimized extraction parameters (Triton X-100 concentration of 0.75% w/v, NaCl concentration of 1.