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101.
102.
Analysis of antioxidant compounds in sweet orange peel by HPLC-diode array detection-electrospray ionization mass spectrometry 总被引:1,自引:0,他引:1
Anagnostopoulou MA Kefalas P Kokkalou E Assimopoulou AN Papageorgiou VP 《Biomedical chromatography : BMC》2005,19(2):138-148
HPLC-diode array detection-electrospray ionization mass spectrometry was used to determine qualitatively and quantitatively the flavonoid content of several fractions and residues of extracts of Greek navel sweet orange peel (Citrus sinensis) from the region of southern Greece (Leonidi-Tripoli). The main groups of flavonoids found according to HPLC retention times, spectral data and literature references were polymethoxylated flavones, C-glycosylated flavones, O-glycosylated flavones, O-glycosylated flavanones, flavonols and phenolic acids and their derivatives. The ethyl acetate fraction which has been shown in previous work to possess the best radical scavenging activity among the others was found to contain C-glycosylated flavones, polymethoxylated flavones, O-glycosylated flavones, O-glycosylated flavanones, two phenolic acid derivatives and two unknown compounds, all in low concentrations. The group of C-glycosylated flavones was reported for the first time in the peel of Navel sweet orange. The C-glycosylated flavones found according to their spectral characteristics and literature were 6-C-beta-glucosyldiosmin, 6,8-di-C-glucopyranosylapigenin, 6,8-di-C-beta-glucosyldiosmin and two unknown. The results suggest that the ethyl acetate fraction of navel Citrus sinensis peel consists of significant antioxidant compounds and can be used as a food additive of natural origin or a pharmaceutical supplement using as a source of peel the byproducts of the orange juice industry. 相似文献
103.
Analytical control of photocatalytic treatments: degradation of a sulfonated azo dye 总被引:1,自引:0,他引:1
Bianco Prevot A Basso A Baiocchi C Pazzi M Marcí G Augugliaro V Palmisano L Pramauro E 《Analytical and bioanalytical chemistry》2004,378(1):214-220
The degradation of Methyl Orange (C14H14N3SO3Na), chosen as a model sulfonated azo dye, was investigated in aqueous solutions containing suspended polycrystalline TiO2 particles under irradiation with simulated sunlight. The dye disappearance and the formation of the mineralization end products were monitored; the formation of the main transient intermediates was also examined in detail. Particular attention was devoted to the identification and to the evolution of fragments retaining the chromophoric group. The comparison of data coming from various analytical techniques led to a possible reaction mechanism for the degradation process, giving insight into an aspect of the treatment which has not been considered in previous studies. 相似文献
104.
Jianhui Sun Xiaolei Wang Jingyu Sun Ruixia Sun Shengpeng Sun Liping Qiao 《Journal of molecular catalysis. A, Chemical》2006,260(1-2):241-246
Sn(IV) doped and nano-sized TiO2 immobilized on active carbon (AC) (Sn(IV)/TiO2/AC) were prepared by the sol–gel and dip-calcination method. An azo dye, Orange G (OG), was used as a model compound to study its photocatalytic activity in a fluidized bed photoreactor. The addition of Sn(IV) on TiO2 could greatly improve the activity of TiO2, and the optimal amount of tin was 2.5 at.%. The effects of calcination temperature, pH value, the initial hydrogen peroxide concentration ([H2O2]0), the catalyst amount ([TiO2]), the initial OG concentration ([dye]0) and co-existing negative ions on the photocatalytic activity of Sn(IV)/TiO2/AC were studied. The optimal conditions were as follows: pH 2.00, [H2O2]0 = 1.5mL/L, [dye]0 = 50 mg/L, [TiO2] = 12.5 g/L, when the 300 W high pressure mercury light was used as the light source. Under these conditions, the degradation efficiency of OG reached 99.1% after 60 min reaction. The kinetics of the OG degradation was also analyzed. The results showed that the kinetics of this reaction fit the Langmiur–Hinshelwood kinetics model well and the absorption of OG on the Sn(IV)/TiO2/AC surface was the controlling step in the whole degradation process. In addition, the catalyst, liquid and gas were separated effectively, and the integrative process of reaction and separation was achieved during the experiment. 相似文献
105.
研究了自制胺修饰酚醛树脂(AMPF)对水溶性染料酸性橙II的吸附性能,探讨了pH值、温度、浓度等因素对酸性橙吸附性能的影响。结果表明,AMPF与市售大孔树脂D296和D301相似,对酸性橙均具有较强的吸附能力。温度升高有利于AMPF对酸性橙的吸附;酸性橙浓度升高,吸附量增大。AMPF对酸性橙的吸附符合Boyd液膜扩散控制。各种树脂对酸性橙的平衡吸附数据符合Langmuir方程和Freundlich等温式,其相关系数大于0.98,n均大于1,表明为优惠吸附。 相似文献
106.
A new method is proposed for the determination ofo-Cresol Red in Xylenol Orange and semi-Xylenol Orange by third-order derivative spectrophotometry at 491 nm in a medium of 0.09 mol/1 sulphuric acid. A linear relationship exists between d3A/d3 and theo-Cresol Red concentration (1–12 g/ml), with a standard deviation of 0.11 g/ml (n = 8) for 10 g/ml ofo-Cresol Red.Presented at the 34th IUPAC Conference (1993) 相似文献
107.
In this work, γ-Fe2O3 and TiO2 NTs/γ-Fe2O3 composites with good magnetism and sonocatalytic activity were prepared by a facile polyol method and utilize the principle of isoelectric point method, respectively. The structural and magnetic features of the prepared calcined γ-Fe2O3 and composite catalysts were investigated by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), surface analysis, UV–Vis diffuse reflectance spectra (UV–Vis DRS), vibrating sample magnetometry (VSM) and zeta potential analysis. The effects of calcination temperature on γ-Fe2O3 phase variation, physical properties and sonocatalytic properties were investigated. The porosity, specific surface area, band gap energy and sonocatalytic activity of γ-Fe2O3 were gradually decreased with calcination temperature increased. TiO2 NTs/γ-Fe2O3 with appropriate composition and specific structural features possess synergetic effects such as efficient separation of charge carriers and hydroxyl radicals produced by heterogeneous fenton and fenton-like reactions. This enhanced the sonocatalytic activity for the degradation of Orange G under ultrasonic irradiation. The sonocatalytic reactions obeyed pseudo first-order kinetics. All these information provide insight into the design and development of high-efficiency catalyst for wastewater treatment. 相似文献
108.
Development of a stir bar sorptive extraction method for the determination of volatile compounds in orange juices 下载免费PDF全文
Carla Herrera Remedios Castro Carmelo García‐Barroso Enrique Durán‐Guerrero 《Journal of separation science》2016,39(18):3586-3593
A stir bar sorptive extraction method for the determination of volatile compounds in orange juices was developed. The extraction variables were optimized using a reduced two‐level factorial screening design (25‐1), and the most suitable analytical conditions for the extraction of the studied compounds were: sample volume 10 mL, extraction time 60 min, stirring speed 1800 rpm, NaCl amount 30% (weight/volume), and twister length 10 mm. The optimized method was further validated, obtaining good linearity and detection and quantification limits low enough to correctly determine the studied compounds. As well, for most of the studied compounds precision and recovery values were good. Several orange juice samples (squeezed and commercial) were extracted following the optimized extraction method and analyzed by gas chromatography coupled to mass spectrometry detection. The method has proven to be suitable for the determination of the aroma of orange juice, of which limonene was the major volatile compound in all the studied samples. 相似文献
109.
建立了阴离子交换色谱-积分脉冲安培法测定脐橙中17种氨基酸的分析方法。样品用无水乙醇提取,经聚苯乙烯-二乙烯基苯型阳离子交换树脂(PS-DVB)003x7去除碳水化合物,采用AminoPac PA10保护柱(50×2mm)和AminoPac PA10分析柱(250×2mm)分离,积分脉冲安培检测器检测。所测17种氨基酸在一定浓度范围内与峰面积呈良好的线性关系,相关系数均大于0.995,检出限为0.01~0.19mg/L。在2.0mg/L和8.0mg/L两个添加水平的平均回收率在72.5%~130.5%之间,相对标准偏差在0.5%~10.1%范围。该法具有较好的准确度和精密度,基本能满足实际样品分析的要求。 相似文献
110.
《Arabian Journal of Chemistry》2021,14(12):103444
In this research, novel CuO-ZnO/ZiF-8 metal–organic frameworks (MOFs) photocatalyst with different mass percentages of ZiF-8 were prepared for water purification applications under visible light. The precipitation method was used to synthesize CuO-ZnO/ZiF-8 photocatalysts. Some techniques, including XRD, FESEM, EDX, BET-BJH, FTIR, DRS, and pHpzc, were performed to determine the structural, chemical, and optical properties of the prepared samples. DRS analysis represented that CuO-ZnO/ZiF-8(20) had narrower band gap energy compared to CuO-ZnO and ZiF-8. Also, BET-BJH analysis results showed that CuO-ZnO had a low surface area that impeded the absorption of pollutant molecules. In contrast, the CuO-ZnO/ZiF-8(20) sample, due to the presence of ZiF-8, had a high specific surface area which enabled higher pollutant adsorption on the photocatalyst surface.Moreover, the synthesized samples were evaluated for the solar-light-driven removal of different organic dyes, such as Acid Orange 7, Methylene blue, and Malachite green. The tremendously enhanced photocatalytic activity under the simulated solar light with 98.1% removal of AO7 was observed over CuO-ZnO/ZiF-8(20) sample. Then, the effect of initial solution pH as an essential factor on photocatalytic activity was investigated. Finally, the reaction mechanism of AO7 degradation over CuO-ZnO/ZiF-8(20) was proposed. 相似文献