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)

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

Electroanalytical overview: utilising micro- and nano-dimensional sized materials in electrochemical-based biosensing platforms.

Research into electrochemical biosensors represents a significant portion of the large interdisciplinary field of biosensing. The drive to develop reliable, sensitive, and selective biosensing platforms for key environmental and medical biomarkers is ever expanding due to the current climate. This push for the detection of vital biomarkers at lower concentrations, with increased reliability, has necessitated the utilisation of micro- and nano-dimensional materials. There is a wide variety of nanomaterials available for exploration, all having unique sets of properties that help to enhance the performance of biosensors. In recent years, a large portion of research has focussed on combining these different materials to utilise the different properties in one sensor platform. This research has allowed biosensors to reach new levels of sensitivity, but we note that there is room for improvement in the reporting of this field. Numerous examples are published that report improvements in the biosensor performance through the mixing of multiple materials, but there is little discussion presented on why each nanomaterial is chosen and whether they synergise well together to warrant the inherent increase in production time and cost. Research into micro-nano materials is vital for the continued development of improved biosensing platforms, and further exploration into understanding their individual and synergistic properties will continue to push the area forward. It will continue to provide solutions for the global sensing requirements through the development of novel materials with beneficial properties, improved incorporation strategies for the materials, the combination of synergetic materials, and the reduction in cost of production of these nanomaterials

Electroanalytical Overview: The Determination of Levodopa (L-DOPA)

L-DOPA (levodopa) is a therapeutic agent which is the most effective medication for treating Parkinson’s disease, but it needs dose optimization, and therefore its analytical determination is required. Laboratory analytical instruments can be routinely used to measure L-DOPA but are not always available in clinical settings and traditional research laboratories, and they also have slow result delivery times and high costs. The use of electroanalytical sensing overcomes these problems providing a highly sensitivity, low-cost, and readily portable solution. Consequently, we overview the electroanalytical determination of L-DOPA reported throughout the literature summarizing the endeavors toward sensing L-DOPA, and we offer insights into future research opportunities

A review of electrochemical impedance spectroscopy for bioanalytical sensors

Electrochemical impedance spectroscopy (EIS) is a powerful technique for both quantitative and qualitative analysis. This review uses a systematic approach to examine how electrodes are tailored for use in EIS-based applications, describing the chemistries involved in sensor design, and discusses trends in the use of bio-based and non-bio-based electrodes. The review finds that immunosensors are the most prevalent sensor strategy that employs EIS as a quantification technique for target species. The review also finds that bio-based electrodes, though capable of detecting small molecules, are most applicable for the detection of complex molecules. Non-bio-based sensors are more often employed for simpler molecules and less often have applications for complex systems. We surmise that EIS has advanced in terms of electrode designs since our last review on the subject, although there are still inconsistencies in terms of equivalent circuit modelling for some sensor types. Removal of ambiguity from equivalent circuit models may help advance EIS as a choice detection method, allowing for lower limits of detection than traditional electrochemical methods such as voltammetry or amperometry