Electroanalysis overview: additive manufactured biosensors using fused filament fabrication

Additive manufacturing (3D-printing), in particular fused filament fabrication, presents a potential paradigm shift in the way electrochemical based biosensing platforms are produced, giving rise to a new generation of personalized and on-demand biosensors. The use of additive manufactured biosensors is unparalleled giving rise to unique customization, facile miniaturization, ease of use, economical but yet, still providing sensitive and selective approaches towards the target analyte. In this mini review, we focus on the use of fused filament fabrication additive manufacturing technology alongside different biosensing approaches that exclusively use antibodies, enzymes and associated biosensing materials (mediators) providing an up-to-date overview with future considerations to expand the additive manufacturing biosensors field

Electrosynthesis of hydrogen peroxide via the reduction of oxygen assisted by power ultrasound

The electrosynthesis of hydrogen peroxide using the oxygen reduction reaction has been studied in the absence and presence of power ultrasound in a non-optimized sono-electrochemical flow reactor (20 cm cathodic compartment length with 6.5 cm inner diameter) with reticulated vitreous glassy carbon electrode (30 x 40 x 10 mm, 10 ppi, 7 cm2 cm-3) as the cathode. The effect of several electrochemical operational variables (pH, volumetric flow, potential) and of the sono-electrochemical parameters (ultrasound amplitude and horn-to-electrode distance) on the cumulative concentration of hydrogen peroxide and current efficiency of the electrosynthesis process have been explored. The application of power ultrasound was found to increase both the cumulative concentration of hydrogen peroxide and the current efficiency. The application of ultrasound is therefore a promising approach to the increased efficiency of production of hydrogen peroxide by electrosynthesis, even in the solutions of lower pH (<12). The results demonstrate the feasibility of at-site-of-use green synthesis of hydrogen peroxide.Ministerio de Educación y Ciencia (Spain) for the Grant (PR2004-0480) and Generalidad Valenciana (Project GV05/104)

Recycled PETg embedded with graphene, multi-walled carbon nanotubes and carbon black for high-performance conductive additive manufacturing feedstock

The first report of conductive recycled polyethylene terephthalate glycol (rPETg) for additive manufacturing and electrochemical applications is reported herein. Graphene nanoplatelets (GNP), multi-walled carbon nanotubes (MWCNT) and carbon black (CB) were embedded within a recycled feedstock to produce a filament with lower resistance than commercially available conductive polylactic acid (PLA). In addition to electrical conductivity, the rPETg was able to hold >10 wt% more conductive filler without the use of a plasticiser, showed enhanced temperature stability, had a higher modulus, improved chemical resistance, lowered levels of solution ingress, and could be sterilised in ethanol. Using a mix of carbon materials CB/MWCNT/GNP (25/2.5/2.5 wt%) the electrochemical performance of the rPETg filament was significantly enhanced, providing a heterogenous electrochemical rate constant, k0, equating to 0.88 (±0.01) × 10−3 cm s−1 compared to 0.46 (±0.02) × 10−3 cm s−1 for commercial conductive PLA. This work presents a paradigm shift within the use of additive manufacturing and electrochemistry, allowing the production of electrodes with enhanced electrical, chemical and mechanical properties, whilst improving the sustainability of the production through the use of recycled feedstock

All-in-one continuous electrochemical monitoring of 2-phenylphenol removal from water by electro-Fenton treatment

The biggest allure of heterogeneous electro-Fenton (HEF) processes largely fails on its high efficiency for the degradation of a plethora of hazardous compounds present in water, but still challenging to search for good and cost-effective electrocatalyst. In this work, carbon black (CB) and oxidised carbon black (CBox) materials were investigated as cathodes in the electrochemical production of hydrogen peroxide involved in HEF reaction for the degradation of 2-phenylphenol (2PP) as a target pollutant. The electrodes were fabricated by employing carbon cloth as support, and the highest H2O2 production yields were obtained for the CBox, pointing out the beneficial effect of the hydrophilic character of the electrode and oxygen-type functionalization of the carbonaceous surface. HEF degradation of 2PP was explored at −0.7 V vs. Ag/AgCl exhibiting the best conversion rates and degradation grade (total organic carbon) for the CBox-based cathode. In addition, the incorporation of an electrochemical sensor of 2PP in line with the HEF reactor was accomplished by the use of screen-printed electrodes (SPE) in order to monitor the pollutant degradation. The electrochemical sensor performance was evaluated from the oxidation of 2PP in the presence of Fe2+ ions by using square wave voltammetry (SWV) technique. The best electrochemical sensor performance was based on SPE modified with Meldola Blue showing a high sensitivity, low detection limit (0.12 ppm) and wide linear range (0.5–21 ppm) with good reproducibility (RSD 2.3 %). The all-in-one electrochemical station has been successfully tested for the degradation and quantification of 2PP, obtaining good recoveries analysing spiked waters from different water matrices origins

Kvantitativna analiza tragova manganovih iona korištenjem voltametrijske redukcije manganova dioksida akumuliranog na površini radne elektrode: ispitivanje svojstava grafitne elektrode s radnom površinom okomitom na slojeve grafita i mogućnosti njene primjene u analizi prirodnih voda

The determination of trace levels of manganese via cathodic stripping voltammetry at an edge plane pyrolytic graphite electrode (eppge) was evaluated for use in environmental analysis. The response of the eppge is compared with boron-doped diamond electrodes under quiescent conditions where the former is observed to have a three times higher sensitivity. Using this protocol with a stirred accumulation period, a detection limit of 14.2 nmol dm–3 and a sensitivity of 14.2 mol dm–3 A–1 is achieved with linearity from 25 to 250 nmol dm–3, based on a 120 seconds accumulation period. The response at a carbon paste electrode is also compared under the same conditions with the eppge found to be superior in terms of sensitivity, detection limits and reproducibility. The efficacy of the protocol utilising the eppge was assessed in the determination of manganese in a certified seawater reference material, NASS-5, from the National Research Council Canada, which was found to be in excellent agreement with the independently verified sample.Istražena je mogućnost određivanja koncentracije manganovih iona u prirodnim vodama korištenjem grafitne elektrode s radnom površinom okomitom na slojeve grafita u kombinaciji s voltametrijskom metodom koja se zasniva na redukciji manganova dioksida akumuliranog na površini radne elektrode. Ako se MnO2 akumulira iz mirne otopine, osjetljivost grafitne elektrode je tri puta veća od osjetljivosti dijamantne elektrode dopirane borom. Kada se akumulacija provodi tokom 120 sekundi uz miješanje otopine, osjetljivost metode je 14,2 mol dm–3 A–1, granica detekcije mangana je 14,2 nmol dm–3, a odziv je linearna funkcija koncentracije mangana u rasponu od 25 do 250 nmol dm–3. Grafitna elektroda osjetljivija je i pouzdanija i od elektrode sačinjene od žitke smjese čađi i mineralnog ulja. Točnost metode potvrđena je mjerenjem koncentracije manganovih iona u referentnom uzorku morske vode (NASS-5, Nacionalni istraživački savjet Kanade)

Electroanalytical overview: the electroanalytical sensing of hydrazine

In this overview, we explore the electroanalytical sensing of the important chemical reagent hydrazine, highlighting the plethora of electrochemical sensing strategies utilised from the first reports in 1951 to the present day. It is observed that a large proportion of the work developing electrochemical sensors for hydrazine focus on the use of metallic nanoparticles and some other surface modifications, although we note that the advantages of such strategies are often not reported. The use of nanoparticle-modified electrodes to this end is explored thoroughly, indicating that they allow the same electrochemical response as that of a macroelectrode made of the same material, with clear cost advantages. It is recommended that significant studies exploring the surface coverage/number of nanoparticles are performed to optimise electroanalytical devices and ensure that thin-layer effects are not producing false observations through electrocatalysis. Development of these sensor platforms has begun to transition away from classical macroelectrodes, toward more mass producible supporting electrodes such as screen-printed and inkjet-printed electrodes. We suggest significant advances in this area are still to be found. The vast majority of developed electroanalytical sensors for hydrazine are tested in aqueous based environments, such as tap, river and industrial effluent waters. There is significant scope for development of hydrazine sensors for gaseous environments and biologically relevant samples such as blood, serum and urine, aiming to produce sensors for accurate occupational exposure monitoring. Finally, we suggest that the levels of publications with independent validation of hydrazine concentrations with other well-established laboratory-based measurements is lacking. We believe that improving in these areas will lead to the development of significant commercial products for the electroanalytical detection of hydrazine

Erratum to “Electroanalytical Overview: The detection of the molecule of murder atropine” [Talatan Open, 2021, 100073](S2666831921000436)(10.1016/j.talo.2021.100073)

The publisher regrets that the Conflict of interest was not published along with the manuscript. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The publisher would like to apologise for any inconvenience caused

Electroanalytical overview: the determination of manganese

Manganese is an essential nutrient of the human body but also toxic at elevated levels with symptoms of neurotoxicity reported, therefore its analytical determination is required. Manganese (II) is ingested primarily through food and drinking water so its routine monitoring in such samples is essential. While laboratory based analytical instrumentation can be routinely used to measure manganese (II), there is a need to develop methods for manganese (II) determination that can be performed in-the-field utilizing simple and inexpensive instrumentation yet providing comparable sensitive analytical measurements. Electrochemistry can provide a solution with instrumentation readily portable and hand-held coupled with electrochemical sensing platforms that are sensitive and provide on-site rapid analytical measurements. Consequently, in this overview we explore the electroanalytical determination of manganese (II) reported throughout the literature and offer insights into future research opportunities within this important field