Yong H. Qi,Hui C. Zhang,Rui T. Xu,Jin Liu,Lei Zhang,Jian P. Wang
The objective of the present study was to develop a multi-analyte immunoassay for the determination of eight red dyes in food samples. Two dye intermediates (2-hydroxy-1-naphthoic acid and 1-amino-2-naphthol) were used as the haptens to produce the monoclonal antibodies. The obtained monoclonal antibodies recognized Sudan 1–4, Para red, Sudan red G, Sudan red B and Acid orange II simultaneously. After evaluation of different antibody/coating antigen combinations, a heterologous indirect competitive enzyme linked immunosorbent assay was developed to determine the eight red dyes in food samples (chili oil, chili powder, tomato sauce, hotpot seasoning). The crossreactivities to the eight analytes were in the range of 61%–79% (with β-naphthol as 100%), and the limits of detection were in the range of 1.3–1.9 ng/mL. The recoveries of the eight analytes from the fortified blank samples were in the range of 84.2%–115% with coefficients of variation lower than 18.3%. Therefore, this method could be used as a rapid and simple tool to detect the residues of the eight red dyes in foods.
Ran-ran Shan,Liang-guo Yan,Yan-ming Yang,Kun Yang,Shu-jun Yu,Hai-qin Yu,Bao-cun Zhu,Bin Du
The Mg–Al-CO 3 -LDH with Mg 2+ /Al 3+ molar ratio of 2 was prepared via coprecipitation method at constant pH of 9–10 and used to remove three red dyes by batch adsorption method. The results showed the Mg–Al-LDH were well crystallized and can adsorb the red dyes effectively. The optimal adsorbent dosage and contact time were 1.0 g and 60 min, respectively. Adsorbed amount hardly changed when pH < 10. The adsorption kinetics fit the pseudo-second order kinetic models well and isotherms correspond to Langmuir model strictly. All the relevant mechanisms were studied and manifested as anion exchange and also electrostatic attraction for CR.
Color filters (CF) are essential integral parts of the liquid crystal display (LCD) and image sensor. Compared to traditional pigment colorants, organic dyes offer a promising alternative to realize CF with improved optical properties and higher resolution. However, organic dyes usually suffer from inferior thermal and photo-stability, limiting their applications in CF. Herein, four robust donor-acceptor organic dyes based on phenanthrenequinone chromophore were designed and synthesized by introducing aromatic amine derivatives as the electron donors. The strong donor-acceptor interactions in these dyes contribute to intense broad charge-transfer absorption bands from 375 nm to 600 nm with high molar extinction coefficients, thus realizing red color. Also, these dyes exhibit high thermal and photo-stability, good compatibility with the polymer binder and low aggregation tendencies, resulting in high thermal and photo-stability for the fabricated CF films. Remarkably, among these phenanthrenequinone dyes, DTPAP with multi-donor substitution and extended π-conjugation exhibited the best performance in terms of molar extinction coefficient, thermal and photo-stability, contributing to the highest thermal and photo-stability for the CF film with color difference values (Δ E ab ) below 0.75 under simulated industrial manufacturing processes. This work confirms that phenanthrenequinone is a robust chromophore and is conducive to developing thermal and photo-stable CF dyes, and paves a way to improve the optical properties and stability of donor-acceptor dyes for CF.