Optical Characterization of Quinoline Yellow Fluorochemosensors for Analyzing Its Photonics Applications With Synthesized Nano Particles

Quinoline Yellow (QY) with the scientific name [sodium 2-(2, 3-dihydro-1,3-dioxo-1H-inden-2-yl) quinoline-6,8-disulfonate] (SQDS) is investigated for its sensing properties as fluorochemosensors and its NLO applications. Pure SQDS is doped with copper ferrite and cerium oxide nanoparticles and studied for changes in spectral results. Change in absorption spectrum is observed depending on the polarity of solvents. Intensity of fluorescence also varies with different type of solvents. Optical characterization for SQDS is carried out via various spectroscopic techniques including UV-VIS spectroscopy, FTIR spectroscopy, Scanning Electron Microscopy and Photo Luminescence (PL) spectroscopy. Optical parameters like extinction coefficient, refractive index and bandgap energy are determined from absorption spectrum for both solution and film samples. XRD characterization is also performed for QY and for nanoparticle doped QY. For investigating Non-Linear optical (NLO) application of QY, films are prepared and optical imaging is performed via Atomic Force Microscopy (AFM). Characterization results are analysed and predicted for application in non-linear optics.

Investigation of the aqueous adsorption capacity of a 6-connected Zr-MOF for anionic and cationic dyes in comparison with other traditional porous materials

A 6-connected Zr-MOF (MOF-808) was successfully synthesized via the solvothermal method with the assistance of formic acid (HCOOH). The resulting MOF showed high crystallinity and thermal stability, which was verified by powder X-ray diffraction (PXRD) measurement, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). As can be expected, the obtained material possessed high porosity with an extremely high specific BET surface area (SABet) of 2372 m2/g. The adsorption capacity of MOF-808 for anionic dyes (i.e. sunset yellow, quinoline yellow, and methyl orange) and cationic ones (i.e. methylene blue and malachite green) in aqueous solutions was respectively investigated. For comparison purpose, the adsorption experiments were also carried out using other traditional porous materials, including commercial microporous activated carbon and synthesized mesoporous SBA-15 with BET surface areas of 1030 m2/g and approximately 800 m2/g, respectively. It was demonstrated that the efficiency of MOF-808 in trapping anionic dyes in water was significantly higher while carbon and silica materials exhibited better performances for the case of cationic dyes.

A cationic surfactant-decorated liquid crystal-based sensor for sensitive detection of quinoline yellow

Quinoline yellow (QY) is one of the popular synthetic food colorants and in food industry greatly used. Developing accurate and simple QY detection procedures is of major considerable importance in ensuring food safety. Hence, it is important to detect this food colorant effectively to reduce risk. Herein, an innovative liquid crystal (LC)-based sensor was designed for the label-free and ultra-sensitive detecting of the QY by means of a cationic surfactant-decorated LC interface. The nematic liquid crystal in touch with CTAB revealed a homeotropic alignment, when QY was injected into the LC-cell, the homeotropic alignment consequently altered to a planar one by electrostatic interactions between QY and CTAB. The designed LC-based sensor detected QY at the too much trace level as low as 0.5 fM with analogous selectivity. The suggested LC-based sensor is a rapid, convenient and simple procedure for label-free detection of QY in food industrial and safety control application.

Evaluation of natural and synthetic dyes in saffron barbecued chicken collected from meat shops and restaurants in Babol using thin-layer chromatography

Synthetic colors have advantages in comparison to natural colors, but they cause cancer, attentiondeficit hyperactivity disorder, immune system suppression and vitamin deficiency. In the present study, authorized and unauthorized synthetic colors in saffron barbecued chicken from meat shops and restaurants in Babol city have been identified by thin-layer chromatography. Fifty samples of saffron barbecued chicken from meat shops and restaurants in Babol city have been collected from July to September 2019. Out of 50 samples, 20 had natural color, while 27 and 3 samples contained authorized and unauthorized synthetic colors respectively. According to the Institute of Standards and Industrial Research of Iran, the application of synthetic colors is banned in saffron barbecued chicken. Therefore, 40% were consumable and 60% were inconsumable, out of which 54% contained quinoline yellow and 6% had tartrazine. About 58.06% and 63.15% of samples from meat shops and restaurants were inconsumable, respectively. There were no significant differences regarding the frequency of the evaluated colors between samples from meat shops and restaurants (p>0.05). Based on the results, it is essential that the presence of synthetic colors is traced constantly and more strictly in food products and that the perpetrators receive more serious punishment.

Efficient Removal of Chromium(VI) Anionic Species and Dye Anions from Water Using MOF-808 Materials Synthesized with the Assistance of Formic Acid

This study presents a simple approach to prepare MOF-808, an ultra-stable Zr-MOF constructed from 6-connected zirconium clusters and 1,3,5-benzene tricarboxylic acid, with tailored particle sizes. Varying the amount of formic acid as a modulator in the range of 200–500 equivalents results in MOF-808 materials with a crystal size from 40 nm to approximately 1000 nm. Apart from the high specific surface area, a combination of a fraction of mesopore and plenty of acidic centers on the Zr-clusters induces a better interaction with the ionic pollutants such as K2Cr2O7 and anionic dyes. MOF-808 shows uptakes of up to 141.2, 642.0, and 731.0 mg/g for K2Cr2O7, sunset yellow, and quinoline yellow, respectively, in aqueous solutions at ambient conditions. The uptakes for the ionic dyes are significantly higher than those of other MOFs reported from the literature. Moreover, the adsorption capacity of MOF-808 remains stable after four cycles. Our results demonstrate that MOF-808 is a promising ideal platform for removing oxometallates and anionic dyes from water.

Photocatalytic Degradation of Quinoline Yellow over Ag3PO4

In this study, the ability of Ag3PO4 to achieve the photocatalytic degradation of quinoline yellow (QY) a hazardous and recalcitrant dye, under UVA and visible light was investigated. The photocatalyst Ag3PO4 was synthesized through a precipitation method, and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), BET Brunauer–Emmett-Teller (BET) analysis, UV-Differential Reflectance Spectroscopy (DRS) and Fourier transform infrared spectroscopy (FTIR). Ag3PO4 could successfully induce the photocatalytic degradation of QY under UVA and visible light. Optimal parameters were 0.5 g·L−1 of the catalyst, 20 ppm of QY and pH~7. Ag3PO4 was 1.6-times more efficient than TiO2 Degussa P25 under UVA light in degrading QY. Total organic carbon (TOC) analyses confirmed the almost complete QY mineralization. At least eight intermediate degradation products were identified by liquid chromatography coupled to high resolution mass spectrometry. The stability of Ag3PO4 was satisfactory as less than 5% Ag metal appeared in XRD analyses after 3 reuse cycles. These results show that under optimized conditions Ag3PO4 can efficiently achieve quinolone yellow mineralization.