A new dioxotetraamine ligand derived from binicotinic acid: synthesis, coordination, and fluorescence behaviour towards divalent transition metal ions

Schiff base derived Fe3+-selective fluorescence turn-off chemsensors based on triphenylamine and indole: synthesis, properties and application in living cells

A Schiff base with an AIE effect could act as a turn-off fluorescent chemosensor for Fe³⁺in living cells.

Voltammetric pH sensing using carbon electrodes: glassy carbon behaves similarly to EPPG

Developing and building on recent work based on a simple sensor for pH determination using unmodified edge plane pyrolytic graphite (EPPG) electrodes, we present a voltammetric method for pH determination using a bare unmodified glassy carbon (GC) electrode. By exploiting the pH sensitive nature of quinones present on carbon edge-plane like sites within the GC, we show how GC electrodes can be used to measure pH. The electro-reduction of surface quinone groups on the glassy carbon electrode was characterised using cyclic voltammetry (CV) and optimised with square-wave voltammetry (SWV) at 298 K and 310 K. At both temperatures, a linear correlation was observed, corresponding to a 2 electron, 2 proton Nernstian response over the aqueous pH range 1.0 to 13.1. As such, unmodified glassy carbon electrodes are seen to be pH dependent, and the Nernstian response suggests its facile use for pH sensing. Given the widespread use of glassy carbon electrodes in electroanalysis, the approach offers a method for the near-simultaneous measurement and monitoring of pH during such analyses.

Voltammetric pH sensor based on an edge plane pyrolytic graphite electrode

A simple sensor for pH determination is reported using unmodified edge plane pyrolytic graphite (EPPG) electrodes. The analysis is based on the electro-reduction of surface quinone groups on the EPPG which was characterised using cyclic voltammetry (CV) and optimised with square-wave voltammetry (SWV). Under optimised conditions, a linear response is observed between the peak potential and pH with a gradient of ∼59 mV per pH (at 25 °C), which corresponds well with Nernstian behaviour based on a 2 proton, 2 electron system over the aqueous pH range 1.0 to 13.0. As such, an EPPG is suggested as a reagent free and robust pH sensing material.

A turn-on fluorogenic Zn(ii) chemoprobe based on a terpyridine derivative with aggregation-induced emission (AIE) effects through nanofiber aggregation into spherical aggregates

The self-assembly of the terpyridine-based ligand exhibited strong emission in the presence of Zn²⁺ due to the formation of coordination bonds between the terpyridine moieties and the Zn²⁺ by the aggregation-induced emission effect.

A self-assembled triphenylamine-based fluorescent chemosensor for selective detection of Fe3+ and Cu2+ ions in aqueous solution

Triphenylamine-based fluorescent chemosensor m-TAPA (S) shows high selectivity and sensitivity toward Fe³⁺/Cu²⁺ in natural and drinking water. Additionally, the TCL strips serve as a simple method for detection of Fe³⁺/Cu²⁺ at the nanomolar range.