Chronoamperometric flow-cell designed to be unaffected by air bubbles.

In this paper, we present a new design for a chronoamperometric flow cell in which air bubbles do not interfere with the control of potential between the working and reference electrodes. The flow-through dual-detection cell consists of two independent parts: an upper compartment containing a quiescent supporting electrolyte solution and a channel that operates under hydrodynamically controlled conditions. In this system, the working and counter electrodes can be placed directly in contact with both compartments, whereas the reference electrode can be assembled to be either isolated or in contact with the flowing stream channel.

Merging 3D-printing technology and disposable materials for electrochemical purposes: A sustainable alternative to ensure greener electroanalysis.

3D-printing technology has revolutionized electrochemical applications by enabling rapid prototyping of various devices with high precision, even in highly complex structures. However, a significant challenge remains in developing less costly and more sustainable analytical approaches and methods aimed at mitigating the negative environmental impacts of chemical analysis procedures. In this study, we propose a solution to these challenges by creating a simple and versatile electrochemical system that combines 3D-printing technology with recyclable disposable materials, such as graphite from an exhausted battery and a stainless-steel screw.

Threads in tubing: an innovative approach towards improved electrochemical thread-based microfluidic devices.

Thread-based microfluidic analytical devices have received growing attention since threads have some advantages over other materials. Compared to paper, threads are also capable of spontaneously transporting fluid due to capillary action, but they have superior mechanical strength and do not require hydrophobic barriers. Therefore, thread-based microfluidic devices can be inexpensively fabricated with no need for external pumps or sophisticated microfabrication apparatus.

Simultaneous quantification of seven multi-class organic molecules by single-shot dilution differential pulse voltammetric calibration.

The contamination of water sources by anthropogenic activities is a topic of growing interest in the scientific community. Therefore, robust analytical techniques for the determination and quantification of multiple substances are needed, which often require complex and time-consuming procedures. In this context, we describe a univariate calibration method to determine emerging multi-class contaminants in different water sources.

Simultaneous separation and electroanalysis in a single polydimethylsiloxane-based platform.

Channel-based microfluidic devices integrating the separation step and detection system are key factors to expand microanalysis application. However, these devices still depend on macroscale external equipment for pre-treatment of the sample, separation, or detection. The integration of all steps in only one stage is critical to improving feasibility.

3D-Printed glycerol microfluidic fuel cell.

A 3D-printed microfluidic fuel cell is presented. Fused deposition modeling is used to build a microchannel with a 0.015 cm cross-sectional area for stable colaminar flow conditions.

An Analytical Evaluation of the Synergistic Effect on Biodiesel Oxidation Stability Promoted by Binary and Ternary Blends Containing Multifunctional Additives.

The antioxidant potential of a novel additive, named maleimide -CH, and the synergistic effect on biodiesel stabilization when combined with a traditional synthetic antioxidant (e.g., propyl gallate (PG)) as well as alternative additives (e.

Electrochemical cell designed for in situ integrate microextraction and electroanalysis: Trace-level determination of norfloxacin in aqueous samples.

In this work, a newly designed electrochemical cell was assembled for in situ integrated microextraction and electroanalysis. Ionic liquids (ILs) were used as extractors to perform the microextraction, which enabled the pre-concentration of norfloxacin from tap water samples. The featured device can be used to replace conventional liquid-liquid microextraction, reducing the number of steps involved in the process.

New Electrochemical Flow-Cell Configuration Integrated into a Three-Dimensional Microfluidic Platform: Improving Analytical Application in the Presence of Air Bubbles.

A newly configured electrochemical flow cell to be used for (end-channel) amperometric detection in a microfluidic device is presented. The design was assembled to place the reference electrode in a separated compartment, isolated from the flow in the microchannel, while the working and counter electrodes remain in direct contact with both compartments. Moreover, a three-dimensional coil-shaped microfluidic device was fabricated using a nonconventional protocol.

Fluorescence Spectroscopy Applied to Monitoring Biodiesel Degradation: Correlation with Acid Value and UV Absorption Analyses.

The techniques used to monitor the quality of the biodiesel are intensely discussed in the literature, partly because of the different oil sources and their intrinsic physicochemical characteristics. This study aimed to monitor the thermal degradation of the fatty acid methyl esters of L. and L.

Sample preparation combined with electroanalysis to improve simultaneous determination of antibiotics in animal derived food samples.

A procedure based on liquid-liquid extraction (LLE) and phase separation using magnetically stirred salt-induced high-temperature liquid-liquid extraction (PS-MSSI-HT-LLE) was developed to extract and pre-concentrate ciprofloxacin (CIPRO) and enrofloxacin (ENRO) from animal food samples before electroanalysis. Firstly, simple LLE was used to extract the fluoroquinolones (FQs) from animal food samples, in which dilution was performed to reduce interference effects to below a tolerable threshold. Then, adapted PS-MSSI-HT-LLE protocols allowed re-extraction and further pre-concentration of target analytes in the diluted acid samples for simultaneous electrochemical quantification at low concentration levels.

Baseline-Corrected Second-Order Derivative Electroanalysis Combined With Ultrasound-Assisted Liquid-Liquid Microextraction: Simultaneous Quantification of Fluoroquinolones at Low Levels.

A baseline-corrected second-order derivative procedure and a miniaturized sample preparation based on low-density solvent and ultrasound-assisted liquid-liquid microextraction (LDS-UA-LLME) was combined to provide the simultaneous electroanalysis of three fluoroquinolones (FQ) as emerging contaminants (ECs). The enhanced mathematical processing provided the best separation with an accurate measurement of the overlapping peaks during the simultaneous electro-oxidation of target FQs that were directly dropped on the surface of carbon nanofiber-modified screen-printed electrodes. The adapted LDS-UA-LLME protocol was the key step involved in the sample preparation, which preconcentrate target analytes from diluted tap water samples with an enrichment factor of around 80×, allowing their quantification at trace levels.

Polarographic determination of sunscreen agents in cosmetic products in micellar media.

This paper introduces a simple, fast and reliable electroanalytical method for differential-pulse polarography based on electrochemical reduction at a dropping mercury electrode. The method was validated for the determination of 2-ethylhexyl-4-methoxycinnamate (EHMC) alone and in association with 4-methylbenzylidene camphor (MBC) or 2-hydroxy-4-methoxybenzophenone (BENZ-3) in samples of commercial cosmetic preparations. The supporting electrolyte that provided the best-defined and most intense peak current for EHMC determination was Britton-Robinson buffer (pH 4.