A series of Amantadine based azo Schiff base dyes 6a-6e have been synthesized and characterized by 1 H NMR and 13 C NMR and evaluated for their in vitro carbonic anhydrase II inhibition activity and antioxidant activity. All of the synthesized showed excellent carbonic inhibition. Compound 6b was found to be the most potent derivative in the series, the IC50 of 6b was found to be 0.0849 ± 0.00245μM (standard Acetazolamide IC50 =0.9975±0.049μM). The binding interactions of the most active analogs were confirmed through molecular docking studies. Docking studies showed 6b is interacting by making two hydrogen bonds w at His93 and Ser1 residues respectively. All compounds showed a good drug score and followed Lipinski's rule. In summary, our studies have shown that these amantadine derived phenolic azo Schiff base derivatives are a new class of carbonic anhydrase II inhibitors. This article is protected by copyright. All rights reserved.

Magnetic solid-phase extraction is an effective and useful technique to preconcentrate trace analytes from food samples. In this study, a magnetic trimeric chromium octahedral metal-organic framework (Fe3O4-NH2@MIL-101) was fabricated and characterized. Fe3O4-NH2@MIL-101 was applied as an adsorbent of magnetic solid-phase extraction combined with high performance liquid chromatography to effectively isolate and simultaneously determine six Sudan dyes (Para Red, Sudan I-IV, and Sudan Red 7B) from tomato sauce. Potential factors affecting the MSPE were investigated in detail, and adsorption efficiency of Fe3O4-NH2@MIL-101 was compared with those of conventional adsorbents, such as neutral alumina, HLB, and C18. The developed method facilitated the extraction with using only 3 mg of adsorbent in 2 min. In addition, enhancement factors of 50, linear range of 0.01-25 μg/mL, and detection limit (S/N = 3) of 0.5-2.5 μg/kg were obtained. The intra-day and inter-day recoveries for spiked Sudan dyes were in the range of 72.6%-92.9% and 69.6%-91.6%, respectively, with relative standard deviations of ≤9.2%.

3D magnetic hollow porous CdFe2O4 microspheres (3D MHPS-CdFe2O4) were prepared by a one-step and template-free hydrothermal method. The material was applied for magnetic solid phase extraction of three azo colorants (Acid Red, Congo Red, Sunset Yellow). Compared to conventional CdFe2O4 nanoparticles, the new 3D material exhibits superior extraction capability because of its unique hollow porous structure, high specific surface area, and the strong interaction between 3D microspheres and the colorants. A magnetic solid phase extraction (MPSE) combined with HPLC was established for simultaneous detection of the three azo colorants in food samples. Under optimum conditions, the detection limits are 0.54-1.00 ng mL-1, and good recoveries of 87.0-100.7% were obtained with spiked samples, with relative standard deviation of ≤ 3.8%. The combination of using the new 3D material and MPSE-HPLC results in an efficient, sensitive and inexpensive method for simultaneous determination of such colorants. Graphical abstract Schematic of the preparation of 3D magnetic hollow porous CdFe2O4 microspheres as solid phase extractant for simultaneous trace detection of three azo colorants in real samples.

An effective and greener mixed hemimicelles magnetic solid phase extraction (MHMSPE) based on magnetic halloysite nanotubes (MHNTs) and ionic liquid (IL) is developed for the simultaneous enrichment and determination of anionic azo dyes in a spiked environmental water sample. In this MHMSPE, the formation of C16mimBr with mixed hemimicelles on the surface of MHNTs leads to the retention of analytes by strong hydrophobic, p-p and electrostatic interactions. This MHMSPE technique combines the advantages of MHNTs and mixed hemimicelles. Zeta potential data demonstrated that mixed hemimicelles were formed in [C16mimBr]/[MHNTs] ratios of the range from 0.15 to 1.33. Different important factors affecting the preconcentration of analytes were investigated and optimized by response surface methodology and one variable at a time. Under the optimum conditions, the limits of detection (LOD) for methyl red and methyl orange (MR and MO) were 0.042 and 0.050 μg L-1 in samples, respectively. The accuracy of the method was assessed by recovery measurements on a spiked sample, and good recoveries 85-87% for MR and 89-93% for MO, with preconcentration factors of 481 and 524, respectively. The low relative standard deviations from 1.6-3.1% for tap water and 2.5-5.4% for lake water was achieved. So far as we know, this is the first development of a mixed hemimicelles SPE based on MHNTs and IL for the extraction of trace anionic azo dyes in environment water samples.

Lipophilicity as key molecular descriptor of potential biological activity for selected derivatives of azo dyes was determined mathematically, by using relevant software packages and by reversed-phase thin-layer chromatography (RPTLC) on C18 and cyano modified carriers in mixtures of water/n-propanol and water/acetone. The obtained chromatographic parameters, RM0 and m, of the examined azo dyes were correlated with the standard measure of lipophilicity, log P, important pharmacokinetic predictors and selected toxicity parameters applying linear regression analysis. Thereby, good correlations for each applied system were obtained (average correlation coefficient, r, 0.944, 0.885 and 0.919). Also, the correlations between the studied parameters of azo dyes were examined applying two multivariate methods (Cluster Analysis and Principal Component Analysis). It was shown that the polarity of the substituent, and to a lesser extent its electronic effects has the greatest influence on the studied parameters of the azo dyes derivatives. Multivariate methods pointed out the similarity of the chromatographic retention constant, RM0, with the parameters of lipophilicity, unlike the chromatographic parameter m, which exhibits better agreement with the toxicity parameters.

Photocatalytic degradation of waste pharmaceutics, with solar radiation, is described here as a feasible method to purify pre-contaminated soils. Phenazopyridine has been used as a model soil contaminant. Two different nano-size powders have been first examined as catalysts, namely commercial TiO2 (anatase) and commercial ZnO. As the ZnO showed higher catalytic efficiency, the study was then focused on it. The commercial ZnO powder was then compared with lab-prepared ZnO powder, and the latter shows relatively higher efficiency. The ZnO was used in two different ways. In one way, dry ZnO catalyst powder was spread onto the soil, while in the other way the ZnO was sprayed onto the soil surface by a wet spray method. The spray technique shows slightly higher efficiency, in addition to being easier to apply at future large scale. Depending on conditions and type of photocatalyst used, up to 90% contaminant removal can be achieved in 30 min. In case of photocatalysis experiments, the reacted contaminant molecules undergo complete degradation with no detectable side reaction organic products. Possible evaporation or escape of organic contaminant, or other possibly resulting organics, is ruled out by a series of control experiments. Photodegradation process takes place only at the catalytic sites on the soil surface, where contaminant molecules that diffuse from the soil bulk are completely degraded. Other useful organisms inside the soil are not affected as they are kept away from catalyst sites. A plausible mechanism is proposed for the degradation process.

Food authenticity and food safety are of high importance to organizations as well as to the food industry to ensure an accurate labeling of food products. Respective analytical methods should provide a fast screening and a reliable cost-efficient quantitation. HPTLC was pointed out as key analytical technique in this field. A new HPTLC method applying caffeine-impregnated silica gel plates was developed for eight most frequently found fat-soluble azo dyes unauthorizedly added to spices, spice mixtures, pastes, sauces, and palm oils. A simple post-chromatographic UV irradiation provided an effective sample cleanup, which took 4 min for up to 46 samples in parallel. The method was trimmed to enable 23 simultaneous separations within 20 min for quantitation or 46 separations within 5 min for screening. Linear (4-40 ng/band) or polynomial (10-200 ng/band) calibrations of the eight azo dyes revealed high correlation coefficients and low standard deviations. Limits of detection and quantification were determined to be 2-3 and 6-9 ng/zone, respectively. After an easy sample extraction, recoveries of 70-120% were obtained from chili, paprika, and curcuma powder as well as from chili sauce, curry paste, and palm oil spiked at low (mainly 25-50 mg/kg) and high levels (150-300 mg/kg). For unequivocal identification, the compound in a suspect zone was eluted via a column into the mass spectrometer. This resulted in the hyphenation HPTLC-vis-HPLC-DAD-ESI-MS. Graphical abstract Simplified clean-up by UV irradiation for Sudan dye analysis in food by HPTLC-vis-HPLC-DAD-ESI-MS.

A simple, fast, green, sensitive and selective ultrasonic assisted deep eutectic solvent liquid-phase microextraction technique was used for preconcentration and extraction of cadmium (Cd) in water and food samples by electrothermal atomic absorption spectrometry (ETAAS). In this technique, a synthesized reagent (Z)-N-(3,5-diphenyl-1H-pyrrol-2-yl)-3,5-diphenyl-2H-pyrrol-2-imine (Azo) was used as a complexing agent for Cd. The main factors effecting the pre-concentration and extraction of Cd such as effect of pH, type and composition of deep eutectic solvent (DES), volume of DES, volume of complexing agent, volume of tetrahydrofuran (THF) and ultrasonication time have been examined in detail. At optimum conditions the value of pH and molar ratio of DES were found to be 6.0 and 1:4 (ChCl:Ph), respectively. The detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD) and preconcentration factor (PF) were observed as 0.023 ng L-1, 0.161 ng L-1, 3.1% and 100, correspondingly. Validation of the developed technique was observed by extraction of Cd in certified reference materials (CRMs) and observed results were successfully compared with certified values. The developed procedure was practiced to various food, beverage and water samples.

A novel and simple method utilizing a chromogenic reaction on filter paper is introduced for the rapid screening of banned aromatic amines released from azo dyes. The proposed method involves the sample preparation protocols outlined by the current standard method and the chromogenic reaction of extracted aromatic amines on filter paper. Based on the principle of the reaction between primary amines and aldehydes, p-dimethylaminobenzaldehyde (DMAB) was used as the chromogenic reagent for the rapid screening of 24 carcinogenic aromatic amines and aniline without any chromatographic instruments under optimized experimental conditions. The detection limit for all the aromatic amines in this study was less than 15 mg/kg. A total of 727 dyed textile samples were analyzed using both the present standard method and the proposed method simultaneously. Using the proposed method, a total of 471 samples did not require further instrumental analysis, which can dramatically save instrumental detection time (61.2%), can decrease instrumental detection costs, and can avoid the use of large amounts of toxic reagents. The proposed method has been applied to detect banned aromatic amines in some inspection institutions and dye factories and has large social and economic benefits. Graphical abstract Chromogenic reaction methods.