RESUMO
This article presents a study on the degradation of a residual textile mixture composed of cationic surfactant cetyltrimethylammonium bromide (CTAB) and the remazol yellow gold RNL-150% and reactive blue BF-5G textile dyes. This was carried out by employing the photo-peroxidation and photo-Fenton processes in LED and UV-C photoreactors. The photo-Fenton process was the most efficient as regards the degradation of the CTAB and dye mixture, for both types of radiation. In the kinetic study, degradations of 99% were obtained in 180 min for the chromophore groups using both types of radiation. The degradation of the CTAB and aromatic groups was, meanwhile, an average of 25% when employing LED radiation. The behavior of the degradation reaction was pseudo-first-order. Toxicity tests indicated that the solutions were better able to grow seeds and bacteria after treatment with the photo-Fenton process, using both types of radiation. The photo-Fenton processes carried out by employing LED and UV-C photoreactors were able to degrade the CTAB and dye mixture, thus highlighting the efficiency of LED radiation when its power (three times smaller) is compared to that of UV-C radiation. This process, therefore, represents an alternative for use in textile wastewater treatment systems.
Assuntos
Peróxido de Hidrogênio , Poluentes Químicos da Água , Compostos Azo , Cetrimônio , Ferro , Oxirredução , Ácidos Sulfanílicos , Têxteis , TriazinasRESUMO
KV3.1 blockers can serve as modulators of the rate of action potential firing in neurons with high rates of firing such as those of the auditory system. We studied the effects of several bioisosteres of N-alkylbenzenesulfonamides, and molecules derived from sulfanilic acid on KV3.1 channels, heterologously expressed in L-929 cells, using the whole-cell patch-clamp technique. Only the N-alkyl-benzenesulfonamides acted as open-channel blockers on KV3.1, while molecules analogous to PABA (p-aminobenzoic acid) and derived from sulfanilic acids did not block the channel. The IC50 of six N-alkyl-benzenesulfonamides ranged from 9 to 55 µM; and the Hill coefficient suggests the binding of two molecules to block KV3.1. Also, the effects of all molecules on KV3.1 were fully reversible. We look for similar features amongst the molecules that effectively blocked the channel and used them to model a blocker prototype. We found that bulkier groups and amino-lactams decreased the effectiveness of the blockage, while the presence of NO2 increased the effectiveness of the blockage. Thus, we propose N-alkylbenzenesulfonamides as a new class of KV3.1 channel blockers.
Assuntos
Ativação do Canal Iônico , Bloqueadores dos Canais de Potássio/química , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Shaw/antagonistas & inibidores , Sulfonamidas/química , Sulfonamidas/farmacologia , Ácido 4-Aminobenzoico/metabolismo , Animais , Linhagem Celular , Lactamas/metabolismo , Camundongos , Neurônios/metabolismo , Dióxido de Nitrogênio/metabolismo , Bloqueadores dos Canais de Potássio/síntese química , Ácidos Sulfanílicos/metabolismo , Sulfonamidas/síntese química , BenzenossulfonamidasRESUMO
A cation exchange matrix with zwitterionic and multimodal properties was synthesized by a simple reaction sequence coupling sulfanilic acid to a chitosan based support. The novel chromatographic matrix was physico-chemically characterized by ss-NMR and ζ potential, and its chromatographic performance was evaluated for lysozyme purification from diluted egg white. The maximum adsorption capacity, calculated according to Langmuir adsorption isotherm, was 50.07 ± 1.47 mg g-1 while the dissociation constant was 0.074 ± 0.012 mg mL-1 . The process for lysozyme purification from egg white was optimized, with 81.9% yield and a purity degree of 86.5%, according to RP-HPLC analysis. This work shows novel possible applications of chitosan based materials. The simple synthesis reactions combined with the simple mode of use of the chitosan matrix represents a novel method to purify proteins from raw starting materials. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:387-396, 2018.
Assuntos
Quitosana/química , Clara de Ovo/química , Muramidase/isolamento & purificação , Ácidos Sulfanílicos/química , Adsorção , Soluções Tampão , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Muramidase/metabolismo , Concentração OsmolarRESUMO
An environmentally reliable analytical methodology was developed for direct quantification of tetracycline (TC) and oxytetracycline (OTC) using continuous flow injection analysis with spectrophotometric detection. The method is based on the diazo coupling reaction between the tetracyclines and diazotized sulfanilic acid in a basic medium, resulting in the formation of an intense orange azo compound that presents maximum absorption at 434 nm. Experimental design was used to optimize the analytical conditions. The proposed technique was validated over the concentration range of 1 to 40 µg mL(-1), and was successfully applied to samples of commercial veterinary pharmaceuticals. The detection (LOD) and quantification (LOQ) limits were 0.40 and 1.35 µg mL(-1), respectively. The samples were also analyzed by an HPLC method, and the results showed agreement with the proposed technique. The new flow injection method can be immediately used for quality control purposes in the pharmaceutical industry, facilitating monitoring in real time during the production processes of tetracycline formulations for veterinary use.
Assuntos
Análise de Injeção de Fluxo/métodos , Tetraciclinas/análise , Colorimetria , Indicadores e Reagentes , Limite de Detecção , Oxitetraciclina/análise , Padrões de Referência , Ácidos Sulfanílicos/química , Tetraciclinas/química , Drogas Veterinárias/análiseRESUMO
Herein, we report the synthesis and mass spectrometry studies of several N-alkylbenzenesulfonamides structurally related to sulfanilic acid. The compounds were synthesized using a modified Schotten-Baumann reaction coupled with Meisenheimer arylation. Sequential mass spectrometry by negative mode electrospray ionization (ESI(-)-MS/MS) showed the formation of sulfoxylate anion (m/z 65) observed in the mass spectrum of p-chloro-N-alkylbenzenesulfonamides. Investigation of the unexpected loss of two water molecules, as observed by electron ionization mass spectrometry (EI-MS) analysis of p-(N-alkyl)lactam sulfonamides, led to the proposal of corresponding fragmentation pathways. These compounds showed loss of neutral iminosulfane dioxide molecule (M-79) with formation of ions observed at m/z 344 and 377. These ions were formed by rearrangement on ESI(+)-MS/MS analysis. Some of the molecules showed antagonistic activity against Kv3.1 voltage-gated potassium channels.
Assuntos
Antibacterianos/química , Bloqueadores dos Canais de Potássio/química , Canais de Potássio Shaw/efeitos dos fármacos , Ácidos Sulfanílicos/química , Sulfonamidas/química , Antibacterianos/síntese química , Desenho de Fármacos , Espectrometria de Massas por Ionização por Electrospray , Sulfonamidas/síntese química , Espectrometria de Massas em TandemRESUMO
This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73-94%) and color (90-94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ~50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.
Assuntos
Compostos Azo/metabolismo , Reatores Biológicos , Corantes/metabolismo , Ácidos Sulfanílicos/metabolismo , Eliminação de Resíduos Líquidos/instrumentação , Aminas/metabolismo , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos/microbiologia , Carbono/metabolismo , Carvão Vegetal , Cor , Desenho de Equipamento , Ácidos Graxos Voláteis/metabolismo , Filtração/instrumentação , Riboflavina/metabolismo , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismoRESUMO
The aim of the present study was to gain further insight on the reliability of the colorimetric determination of the activity of bacterial nitrate reductase to evaluate bacterial concentrations and interaction between microorganisms and enterocyte-like cells. Nitrite produced after incubation of the samples with a nitrate-formate solution was determined with a diazotization reaction with sulphanilic acid and N-naphthyl-ethylene-diamonium dichloride. Cell association assays were performed with differentiated Caco-2 cells. A biphasic relationship was found between nitrite concentration and bacterial densities. This behavior seems to be due to the sigmoideal character of the kinetics of nitrate reduction. Association to Caco-2 cells was strongly strain dependent being Staphylococcus aureus ATCC 25923 the strain showing the highest values of association. For some strains, percentages of association calculated on the basis of the colorimetric assay were significantly higher than those calculated in terms of viable counts. Bacterial association with enterocyte-like cells can be evaluated by measures of the activity of bacterial nitrate reductase provided that the biphasic relationship between bacterial and nitrite concentrations is taken into account for the calculations. Results presented in this paper show the applicability of the colorimetric method to assess the amount of microorganisms associated to human enterocytes in culture.