A dual channel fluorescence tongue for catechin recognition based on the MnO₂ nanorods–Amplex Red–o-phenylenediamine reaction system

Abstract

Here, we report a dual-channel fluorescence sensor array for catechin discrimination based on the MnO2 nanorods (NRs)–Amplex Red (AR)–o-phenylenediamine (OPD) catalytic reaction system.

Monitoring Different Water Types for Engine Oil–Water-Soluble Fraction and Iron(2+) Using a Reaction-Based Optical Sensing Strategy: A Proof-of-Concept Study

“…The methodology as a whole is empirical, so the search for indicator reactions is empirical, too. However, the selection can be facilitated by using the pool of reactions previously developed for the discrimination of various samples. − …”

“…Most commonly, optical fingerprinting of samples was based on absorbance or intrinsic fluorescence measurements . The use of dyes to produce colorimetric sensor arrays started in late 1990s, and the addition of fluorophores to samples has been practiced since 2007; the latter approach makes it possible to measure intrinsic emission along with the fluorophore signal that is dependent on the composition of the sample. , Since late 2010s, a kinetic version of the technique has been employed, in which an indicator reaction (such as dye oxidation) is conducted in the presence of samples to be discriminated. − The kinetic approach adds dimensionality to the optical data on the one hand and allows to obtain signals from compounds and samples that do not exhibit intense fluorescence or absorption and do not form colored complexes, etc., on the other hand. This strategy showed its efficiency in the discrimination of bottled mineral waters, rennet samples, engine oils, and estimation of doses received by irradiated food. , …”