RESUMO
Increasing interest in green chemistry has led scientists to an environmentally friendly nanoparticle synthesis approach that has many advantages, such as simple, affordable and versatility for a wide range of commercial production. In this study, green synthesis of zinc oxide nanoparticles (ZnO NPs), which is widely researched in the field of nanotechnology, was performed under different conditions (volume ratio of CC flower extract to Zn(CH3COO)2 solution, time, pH and temperature) using the aqueous extract of Amarant (Celosia cristata L., CC, cockscome) plant flowers. Produced ZnO NPs were characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM) and scanning electron microscopy (SEM) analysis. The characteristic absorption peak seen at λmax: 364 nm in the UV-Vis absorption spectrum and the band seen at 381 cm-1 in the FTIR spectrum indicate that ZnO NPs were synthesized. TEM image also confirmed the formation of nanoparticles. The average size of nanoparticles is approximately 22-27 nm and the shape of the ZnO NPs as nearly spherical. The effect of different calcination temperatures (100, 200, 300, 400, and 500 °C) on the size of ZnO NPs was investigated and it was observed that the particle size decreased as the calcination temperature increased. ZnO NPs were also used as photo catalyst for removal of basic yellow28 (BY28) and basic violet39 (BV39) dyestuffs which are used in textile industry and ecologically toxic. The decolorization efficiency was found 95%-100% and 62% respectively when the BV39 and BY28 dyestuffs were exposed to UV light for 160 min. Antibacterial activity of ZnO NPs produced with different amounts of CC flower extract and calcined at different temperatures (100, 200, 300, 400, and 500 °C) was investigated using modified disc diffusion method. Produced ZnO NPs displayed antibacterial activity against Staphylococcus aureus and Escherichia coli bacterial strains and were more effective against gram-positive pathogens. The findings displayed that the antibacterial activity of ZnO NPs is related to the particle size. This new environmentally friendly synthesis approach is a suitable technique for large-scale commercial production and can be considered as an alternative to chemical methods.
RESUMO
Background: Synthetic colorants are largely used in the pharmaceutical products to increase the attractiveness of products and to help patients distinguish between pharmaceuticals. Despite their commercial advantages, synthetic colorants may, in some cases, have a negative impact on the human body. It is therefore imperative to measure the quantities in food products and pharmaceuticals with a fast, reliable, and sensitive method. Objective: The analyzed synthetic colorants in this study are Erythrosine [(E) E127], Quinoline Yellow [(QY) E104], and Indigo Carmine [(IC) E132]. The aim of this study was to develop and validate a new method for the preconcentration and simultaneous determination of these colorants in pharmaceutical preparations. Method: The developed method has many advantages such as novelty, sensitivity, cost effectiveness, speed, and environmental friendliness. This method is based on the cloud-point extraction (CPE) method coupled with first-derivative spectrophotometry (FDS). In the proposed method, QY, E, and IC were extracted from an aqueous solution by using mixed micelles of TritonX-100 and cetyltrimethylammonium bromide. The effect of the main parameters such as solution pH, surfactant and salt concentration, incubation time, and temperature on the CPE of colorants were investigated and optimized. Under the optimal conditions, the extracted surfactant-rich phase was diluted with acetone, and the first-derivative absorbance values were measured at wavelengths 408, 497, and 637 nm for QY, E, and IC, respectively. The CPE-FDS method was applied in the range of 1.0-6.0 µg/mL for E and QY, and 0.3-1.8 µg/mL for IC. Results: The results showed higher correlation coefficients of 0.9990-0.9993 for each colorant. Furthermore, the method was validated for precision and accuracy and assessed the colorants' contents in the synthetic mixtures that contained different ratios of colorants and pharmaceutical samples. The LOD and LOQ values were 31.0 and 103.0 ng/mL for E, 57.0 and 190.0 ng/mL for QY, and 48.0 and 160.0 ng/mL for IC, respectively. The RSDs at the intermediate concentration level (1.2 µg/mL for IC and 3 µg/mL for QY and for E) were <5%. The recovery values in different ratios of colorants were in the ranges of 90.42-101.14, 92.40-105.54, and 96.15-101.25% for E, IC, and QY, respectively. CPE-FDS was also successfully applied to the simultaneous analysis of the QY, IC, and E contents in the various pharmaceutical samples. The obtained results were statistically compared with those obtained by the green HPLC method that was previously reported by Yoshioka et al. and modified by us in this study. Conclusions: The data observed indicated that the CPE-FDS method does not require use of great samples for determination of trace amounts of E, IC, and QY and allows for the determination of analytes in high matrix effect samples such as suspension and syrup. The study concludes that the proposed CPE-FDS method could be considered an alternative to the existing chromatographical methods for the simultaneous determination of trace amounts of E, IC, and QY in pharmaceutical dosage forms for routine analysis. Highlights: A new and effective procedure, simultaneous determination, trace amounts of E, QY, and IC was developed. This is the first report that uses CPE coupled with FDS for the analysis of E, QY, and IC. CPE avoids the use of costly, hazardous, and flammable solvents in large quantities. FDS resolves two or three overlapping spectra and eliminates matrix interferences. CPE-FDS did not require use of large samples for determination of trace colorants.
