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1.
基于金属有机骨架的拓扑三维结构的高比表面积以及金纳米颗粒(Au NPS)的优异电催化活性,金纳米颗粒与金属有机框架的复合材料在电化学传感领域拥有应用潜力。该文成功合成了Au NPs@NU-901复合材料,并采用透射电镜、X射线衍射、红外光谱以及X射线光电子能谱对其进行表征。采用线性扫描伏安法和差分脉冲伏安法研究了复合材料对丁基羟基茴香醚(BHA)电化学氧化反应的催化能力。结果表明,Au NPs@NU-901对BHA的电化学氧化具有较好的催化能力。基于Au NPs@NU-901制备电化学传感器用于BHA的定量检测,BHA的氧化峰电流与其浓度在0.10~50 μmol/L范围内呈现良好线性关系,相关系数(r2)为0.994 8,检出限(S/N=3)为0.049 μmol/L,相对标准偏差(RSD)为3.6%。将该传感器应用于饼干样品中BHA的检测,加标回收率为95.6%~104%,样品检测结果与高效液相色谱法的测定结果吻合。方法的选择性好、灵敏准确,适合于饼干中BHA的检测。 相似文献
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Hanene Zemmouri Sonda Ammar Amel Boumendjel Mahfoud Messarah Abdelfattah El Feki Mohamed Bouaziz 《Arabian Journal of Chemistry》2019,12(8):1954-1963
The aqueous and hydroalcoholic extracts of borage (Borago officinalis) leaves from Annaba region (Algeria) were preliminary analyzed for their phenolic profile (total phenolics, total flavonoids, total flavonols, total tannins and total anthocyanins). These extracts were evaluated for their antioxidant properties by different methods such as DPPH radical scavenging, test NBT and total antioxidant activity. The two extracts have exhibited a high antiradical capacity. Indeed, the ethanolic extract showed the lower IC50 values and the highest amount of phenolics (94.09 ± 1.72 mg gallic acid/g dry extract). Using LC-MS/MS analysis, it was possible to identify phenolic acids, flavonoids, sterol and for the first time oleuropein was identified in the aqueous extract of the plant. The obtained results have demonstrated that phenolic compounds are the major contributor to the antioxidant activity of plants. 相似文献
3.
Robert M. Ianniello 《Mikrochimica acta》1989,98(1-3):1-6
A direct voltammetric method for the rapid determination of butylated hydroxytoluene has been developed. The procedure utilizes a hydrolyzed cellulose acetate film in intimate contact with a glassy carbon electrode and square wave voltammetry. The coated electrode prevents passivation due to adsorption of polymeric oxidation products by way of a size exclusion principle. BHT solutions containing lipid-like surfactants can be analyzed without the need for frequent resurfacing of the electrode. 相似文献
4.
Continuous flow injection and UV spectrophotometric detection have been proposed for simultaneous determination of the two binary mixtures, butylated hydroxytoluene (BHT)/n-propyl gallate (n-PG) and butylated hydroxytoluene (BHT)/butylated hydroxyanisole (BHA), in food and cosmetics samples. The method is based on the different residence times of each antioxidant when the flow cell is packed to a height of 25 mm with silica C18 using methanol-water 50:50% (v/v) as a carrier with a flow rate of 1.25 and 1.10 ml min−1, respectively. The determination of each antioxidant is based on the measurement of its absorbance at its maximum wavelengths using a DAD detector at 30 and 180 s for the mixture n-PG-BHT and 90 and 220 s for BHA-BHT. Calibration graphs were linear over the range 10.0-300.0 μg ml−1 for each antioxidant in both mixtures. The relative standard deviations were 2.5% for BHT and 2.0% for the co-existing antioxidant. Resolution of the n-PG-BHT mixture in ratios between 1:8 and 8:1 and the BHA-BHT mixture in ratios between 1:10 and 10:1 is possible. The method was applied to the determination of both antioxidants in fat foods and cosmetics samples with recoveries ranging between 101 and 105%. 相似文献
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《Arabian Journal of Chemistry》2022,15(12):104368
Protein hydrolysates have the potential to be natural and safer sources of bioactive peptides. In this study, two proteases were used to hydrolyze Chinese sturgeon (Acipenser sinensis) protein, and the hydrolysates were then purified to yield antioxidant peptides. The degree of hydrolysis of 23.56 % and 18.14 % was obtained using papain and alcalase 2.4L, respectivly, and hydrolysates had 96.80 % and 87.24 % total amino acid content, respectivly. The papain hydrolysate (PH) and alcalase 2.4L hydrolysate (AH) showed good antioxidant activity against DPPH? (IC50 of 3.64 and 3.15 mg/mL) and ABTS?+ (IC50 of 1.92 and 1.58 mg/mL), respectively. The low-molecular-weight (<1000 Da) fraction of both hydrolysates demonstrated the highest antiradical activity (IC50 of 2.59 and 2.31 mg/mL, DPPH) and (IC50 of 1.54 and 1.36 mg/mL, ABTS), respectively. Nine peptides were separated from both hydrolysates using reverse phase high performance liquid chromatography (RP-HPLC). The IC50 for ABTS?+ scavenging activity of peptide P5 with valine, glycine and asparagine (MW of 282.13 Da) from PH, and peptide P3 with histidine, glycine and alanine (MW of 302.74 Da) from AH was 0.89 and 0.72 mg/mL, respectively. The fractions and purified peptides obtained from Chinese sturgeon hydrolysates could be utilized as natural antioxidant substitutes in pharmaceuticals and food products. 相似文献
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《Acta Crystallographica. Section C, Structural Chemistry》2018,74(5):548-557
A new packing polymorph of bis(2,6‐di‐tert‐butyl‐4‐methylphenolato‐κO)bis(tetrahydrofuran‐κO)magnesium, [Mg(C15H23O)2(C4H8O)2] or Mg(BHT)2(THF)2, (BHT is the 2,6‐di‐tert‐butyl‐4‐methylphenoxide anion and THF is tetrahydrofuran), ( 1 ), has the same space group (P21) as the previously reported modification [Nifant'ev et al. (2017d). Dalton Trans. 46 , 12132–12146], but contains three crystallographically independent molecules instead of one. The structure of ( 1 ) exhibits rotational disorder of the tert‐butyl groups and positional disorder of a THF ligand. The complex of bis(2,6‐di‐tert‐butyl‐4‐methylphenolato‐κO)bis(μ2‐ethyl glycolato‐κ2O,O′:κO)dimethyldialuminium, [Al2(CH3)2(C4H7O3)2(C15H23O)2] or [(BHT)AlMe(OCH2COOEt)]2, ( 2 ), is a dimer located on an inversion centre and has an Al2O2 rhomboid core. The 2‐ethoxy‐2‐oxoethanolate ligand (OCH2COOEt) displays a μ2‐κ2O,O′:κO semi‐bridging coordination mode, forming a five‐membered heteronuclear Al–O–C–C–O ring. The same ligand exhibits positional disorder of the terminal methyl group. The redetermined structure of the heptanuclear complex octakis(μ3‐benzyloxo‐κO:κO:κO)hexaethylheptazinc, [Zn7(C2H5)6(C7H7O)8] or [Zn7(OCH2Ph)8Et6], ( 3 ), possesses a bicubic Zn7O8 core located at an inversion centre and demonstrates positional disorder of one crystallographically independent phenyl group. Cambridge Structural Database surveys are given for complexes structurally analogous to ( 2 ) and ( 3 ). Complexes ( 2 ) and ( 3 ), as well as derivatives of ( 1 ), are of interest as catalysts for the ring‐opening polymerization of ϵ‐caprolactone, and polymerization results are reported. 相似文献
9.
Robert H. Sik Carl S. Paschall Colin F. Chignell 《Photochemistry and photobiology》1983,38(4):411-415
Abstract— Benoxaprofen [2-(4-chlorophenyl)-α-methyl-5-benzoxazoleacetic acid] is a phototoxic non-steroidal anti-inflammatory agent. Irradiation of human erythrocytes in the presence of benoxaprofen (8 μ M ) and oxygen resulted in rapid cell lysis which began after 10 min and was complete within 30 min. While photohemolysis was also observed under anerobic conditions, its onset was delayed for more than 20 min and it took nearly 100 min for complete lysis to occur. Photohemolysis was also delayed by butylated hydroxyanisole but was unaffected by reduced glutathione. 1,4-diazabicyclo[2.2.2]octane, D2 O. β-carotene, or superoxide dismutase. The main photoproduct of benoxaprofen, 2-(4-chlorophenyl)-5-ethylbenzoxazole, was almost as effective in causing photohemolysis as benoxaprofen itself. In the presence of UV irradiation, benoxaprofen (10 (μ M ) caused the degranulation of rat peritoneal mast cells and the release of histamine. The release of mast cell histamine may provide a reasonable explanation for the urticarial response to benoxaprofen and irradiation seen in human subjects. 相似文献
10.
Kellen Heloizy Garcia Freitas 《Talanta》2010,81(3):1102-12
A simple electrochemical method was developed for the single and simultaneous determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in food samples using square-wave voltammetry (SWV). A carbon composite electrode modified (MCCE) with copper (II) phosphate immobilized in a polyester resin was proposed. The modified electrode allowed the detection of BHA and BHT at potentials lower than those observed at unmodified electrodes. A separation of about 430 mV between the peak oxidation potentials of BHA and BHT in binary mixtures was obtained. The calibration curves for the simultaneous determination of BHA and BHT demonstrated an excellent linear response in the range from 3.4 × 10−7 to 4.1 × 10−5 mol L−1 for both compounds. The detection limits for the simultaneous determination of BHA and BHT were 7.2 × 10−8 and 9.3 × 10−8 mol L−1, respectively. In addition, the stability and repeatability of the electrode were determined. The proposed method was successfully applied in the simultaneous determination of BHA and BHT in several food samples, and the results obtained were found to be similar to those obtained using the high performance liquid chromatography method with agreement at 95% confidence level. 相似文献