Raman spectrometry as a screening tool for solvent-extracted azo dyes from polyester-based textile fibres

Abstract

Some types of textile fibres are considered to be the cause of allergic reactions and other adverse health effects on humans. The main compounds behind these health problems usually contain azo groups in their chemical structure, which are widely employed as azo dyes in the manufacture of textile and clothing products. In this respect, availability of simple analytical procedures for identifying azo groups in textiles is of concern, not only for toxicological studies, but also for clinical and forensic investigations. In this work, conventional Raman spectrometry was assessed as an analytical tool for identification of the azo function in the extracts of fibres obtained after applying a liquid-solvent extraction procedure to the polyester-based textile products. A mediumpolarity solvent of ethanol-diethyl ether (1:1 mixture) was shown to be the most effective extraction medium. Two laser lines at 514.5 nm and 785 nm were compared, with the longer wavelength preferred as additional peaks were identified in the Raman spectrum, which had better signal-to-background and signal-to-noise ratios owing to decreased fluorescence in contrast to excitation at 514.5 nm. The method reported is a convenient procedure that can be applied in many instances when rapid screening of fibre dyes is required.

Highly selective hydrogen peroxide electrosynthesis on copper phthalocyanine: interface engineering with an azo-polymer

“…An obvious Raman band at 1403 cm −1 corresponds to the azo bond. The characteristic peaks at 1338 cm −1 , 1449 cm −1 and 1524 cm −1 belong to the Pc structure, representing the C-C vibration of benzenoid rings, C-C and C]N vibrations of isoindole and C-N]C vibration in the bridge position, 48,49 respectively. These results further indicate that the structure of copper phthalocyanine is well retained and successfully embedded in azo-polymer macromolecules.…”

A Novel Azo‐Linked Polymer Bearing Trifluoromethyl Groups for I2 Capture

“…[ 42 ] Moreover, there is an obvious band at 1408 cm −1 in Raman spectrum (Figure S5, Supporting Information), which corresponds to the azo bond from the literature. [ 43 ]…”

“…[42] Moreover, there is an obvious band at 1408 cm −1 in Raman spectrum (Figure S5, Supporting Information), which corresponds to the azo bond from the literature. [43] Figure 2b demonstrates the thermal stability of Azo-Car-CF 3 which could remain stable at temperatures reaching up to 300 °C under N 2 atmosphere. The weight loss could be observed because of the desorption of solvent.…”

Electrochemical Thin‐Film Transistors using Covalent Organic Framework Channel

“…[ 35 ] The small peak at ≈1450 cm −1 and ≈1140 cm −1 are identified as NN stretch and C–N symmetrical stretch. [ 36 ] The broad peak centered at ≈2830 cm −1 is denoted as C–H stretching. [ 37 ] On the other hand, the crystallinity of the COF films is very important.…”