Indicator Layers Based on Ethylene-Vinyl Acetate Copolymer (EVA) and Dicyanovinyl Azobenzene Dyes for Fast and Selective Evaluation of Vaporous Biogenic Amines

Abstract

The article presents naked-eye methods for fast, sensitive, and selective detection of isopentylamine and cadaverine vapours based on 4-N,N-dioctylamino-4′-dicyanovinylazobenzene (CR-528) and 4-N,N-dioctylamino-2′-nitro-4′-dicyanovinylazobenzene (CR-555) dyes immobilized in ethylene-vinyl acetate copolymer (EVA). The reaction of CR-528/EVA and CR-555/EVA indicator layers with isopentylamine vapours caused a vivid colour change from pink/purple to yellow/orange-yellow. Additionally, CR-555/EVA showed colour changes upon exposure to cadaverine. The colour changes were analysed by ultraviolet–visible (UV/VIS) molecular absorption spectroscopy for amine quantification, and the method was partially validated for the detection limit, sensitivity, and linear concentration range. The lowest detection limits were reached with CR-555/EVA indicator layers (0.41 ppm for isopentylamine and 1.80 ppm for cadaverine). The indicator layers based on EVA and dicyanovinyl azobenzene dyes complement the existing library of colorimetric probes for the detection of biogenic amines and show great potential for food quality control.

Sensitive 1,1-dicyanovinyl push-pull dye for primary amine sensing in solution by fluorescence

“…This is in agreement with an imine structure in which the push-pull character is preserved but a weaker electron-acceptor group is present. A simple nucleophilic reaction at the Cβ position, as assumed by Finšgar et al for similar dicyanovinyl azobenzene dyes [26] or as is observed with thiols [25] and the cyanide anion, [35,42] would lead to a drastic upfield shift of the proton originally at the β-position as well as those of the closest thiophene ring due to a disruption of the π-conjugation from the donor to the acceptor end. The imine structure was further confirmed by mass spectrometry and the independent synthesis of PTT-imine from aldehyde 1 and n-propylamine (Scheme 1), whose 1 H and 13 At the same time, an intense emission appeared at 535 nm that steadily increased while adding amine.…”

“…Mohr et al also described a colorimetric read-out sensor based on push-pull azo dye and therefore working at wavelengths compatible with low-cost light sources and detectors. [25,26] However in all these works, the end product was not characterized or simply postulated as being the 1,2 adduct. [26] Sathiyanarayanan et al reported the design of a ratiometric PL sensor for primary amine based on a dicyanovinyl substituted phenanthridine derivatives and they clearly identified the end product as being the corresponding imine.…”

“…[25,26] However in all these works, the end product was not characterized or simply postulated as being the 1,2 adduct. [26] Sathiyanarayanan et al reported the design of a ratiometric PL sensor for primary amine based on a dicyanovinyl substituted phenanthridine derivatives and they clearly identified the end product as being the corresponding imine. [27] Finally, in 2020, Burn, Show and coworkers reported two dicyanovinylfluorene-benzothiadiazole-based fluorescent compounds, which showed rapid response to a wide range of amines.…”

Addressing the Needs of the Rapidly Aging Society through the Development of Multifunctional Bioactive Coatings for Orthopedic Applications

“…In ethylene–vinyl acetate copolymers (EVAs), polar vinyl acetate units are randomly dispersed in the backbone. These non-biodegradable polymers are used in a variety of commercial applications, such as stent coatings, intravitreal implants, contraceptive implants, and intravaginal contraceptive rings [ 134 ]. SurModics Bravo™ (a blend of poly-butyl methacrylate and polyethylene vinyl acetate polymers) is a product used as a coating for stainless steel Cypher™ stents (Cordis, Santa Clara, CA, USA) that releases the immunosuppressant rapamycin [ 135 ].…”

Dipsticks with Reflectometric Readout of an NIR Dye for Determination of Biogenic Amines

“…Frequently, chromogenic and fluorogenic dyes, such as acid-base indicators [14][15][16] porphyrins [17], phthalocyanines [18], chameleon dyes [19,20], coumarin derivatives [21], azo dyes [22,23], or nanomaterials are applied for optical BA determination. Cellulose-based microparticles bonded with a pH-indicator and a blue reference dye yielded in slow traffic light-responding (1.5 h) colorimetric sensors [16].…”