Carbon Materials in Electroanalysis of Preservatives: A Review

Electrochemical sensors in electroanalysis are a particularly useful and relatively simple way to identify electroactive substances. Among the materials used to design sensors, there is a growing interest in different types of carbon. This is mainly due to its non-toxic properties, low cost, good electrical conductivity, wide potential range, and the possibility of using it in both aqueous and nonaqueous media. The electrodes made of carbon, and especially of carbon modified with different materials, are currently most often used in the voltammetric analysis of various compounds, including preservatives. The objective of this paper is to present the characteristics and suitability of different carbon materials for the construction of working electrodes used in the voltammetric analysis. Various carbon materials were considered and briefly discussed. Their analytical application was presented on the example of the preservatives commonly used in food, cosmetic, and pharmaceutical preparations. It was shown that for the electroanalysis of preservatives, mainly carbon electrodes modified with various modifiers are used. These modifications ensure appropriate selectivity, high sensitivity, low limits of detection and quantification, as well as a wide linearity range of voltammetric methods of their identification and determination.

Nickel(ii) monobenzoporphyrins and chlorins: synthesis, electrochemistry and anion sensing properties

New NiII monobenzoporphyrins and chlorins were synthesized. One compound was used as a chemodosimeter for naked-eye detection of cyanide in nonaqueous media giving a new π-extended porphyrin product with NIR absorptions and a 1.47 V HOMO–LUMO gap.

Asymmetric Organocatalyzed Warfarin Synthesis in aqueous and nonaqueous media: A discussion in the era of COVID-19 pandemic

: The recent widespread infection of COVID-19 in the entire world has created pandemic situation with a serious health challenge to the mankind. Numerous incidents of cardiovascular disease were found among COVID-19 patients with a significantly high morbidity rate. Medication with several anticoagulant or blood thinner drugs are being performed on COVID-19 patients with atrial fibrillation and cardiovascular ailments to minimize the incidence of death. Warfarin is widely used anticoagulant and cardiovascular drug prescribed as its sodium salt. S-Enantiomer is two to five times more active than R-enantiomer as anticoagulant. Synthesis of enantiomerically pure warfarin is thus a rational and extremely important task. Organocatalyzed synthetic strategies may be considered as important avenues to produce optically pure warfarin in comparison to biocatalysis and chiral metal complex catalysis. Herein, a comprehensive review on the asymmetric organocatalyzed synthesis of warfarin catalysed by diamine based organocatalysts, amino acid based organocatalysts, quinine based organocatalysts and proline derived organocatalysts in both aqueous and non-aqueous media has been discussed.

Thiophene-based Schiff base ligand as ionophore for Ni(II)-selective polyvinyl chloride membrane electrode

A synthesized Schiff base 2-acetylthiophene semicarbazone (3) was used for the preparation of Ni2+ selective polyvinyl chloride (PVC) membrane electrode. The prepared electrode with the optimized composition, PVC:3:sodium tetraphenylborate:di-n-butylphthalate as 33:6:3:58 exhibited a Nernstian response over the working range of 5.0 × 10−6–5.0 × 10−2 mol l−1 with a slope of 29.0 ± 0.3 mV/concentration. The electrode showed good selectivity towards Ni2+ with respect to several metal ions in the pH range of 2.5–10.0 in <15 s with a detection limit of 4.7 × 10−6 mol l−1. The electrode showed the additional benefit of working in partially nonaqueous media having up to 15% (v/v) methanol or ethanol. This electrode was also successfully applied in Ni2+ ion potentiometric titration with ethylenediaminetetraacetic acid as an indicator electrode.