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1.
Carotenoids are an essential component of cashew and can be used in pharmaceuticals, cosmetics, natural pigment, food additives, among other applications. The present work focuses on optimizing and comparing conventional and ultrasound-assisted extraction methods. Every optimization step took place with a 1:1 (w:w) mixture of yellow and red cashew apples lyophilized and ground in a cryogenic mill. A Simplex-centroid design was applied for both methods, and the solvents acetone, methanol, ethanol, and petroleum ether were evaluated. After choosing the extractor solvent, a central composite design was applied to optimize the sample mass (59–201 mg) and extraction time (6–34 min). The optimum conditions for the extractor solvent were 38% acetone, 30% ethanol, and 32% petroleum ether for CE and a mixture of 44% acetone and 56% methanol for UAE. The best experimental conditions for UAE were a sonication time of 19 min and a sample mass of 153 mg, while the CE was 23 min and 136 mg. Comparing red and yellow cashews, red cashews showed a higher carotenoid content in both methodologies. The UAE methodology was ca. 21% faster, presented a more straightforward composition of extracting solution, showed an average yield of superior carotenoid content in all samples compared to CE. Therefore, UAE has demonstrated a simple, efficient, fast, low-cost adjustment methodology and a reliable alternative for other applications involving these bioactive compounds in the studied or similar matrix.  相似文献   
2.
利用标量化方法建立对称向量拟均衡问题有效解的存在性定理。作为标量化方法的应用,利用这一方法得到向量变分不等式和拟向量变分不等式有效解的存在性定理。  相似文献   
3.
A highly selective molecularly imprinted polymer sorbent was synthesized and employed for the simultaneous determination of six sulfonamide antibiotic residues (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine, and sulfamethizole) in milk samples. Multi‐analyte imprinted particles were used as a sorbent in solid‐phase extraction. Sulfonamides were separated on a high‐performance liquid chromatography column (Merck–Lichrospher RP18e, 5 μm 250 × 4 mm) and further identified and quantified by diode array detection. Several parameters including required loading of the molecularly imprinted polymer sorbent, mass of milk, volume, and type of elution solvent, as well as time for absorption and elution were investigated to obtain optimal experimental conditions. For comparison purpose, a non‐imprinted polymer was applied under the optimum conditions. The validation study according to the European Union Decision 2002/657/EC was based on the investigation of linearity, selectivity, stability, limits of detection and quantitation, decision limit, detection capability, trueness, precision, and ruggedness according to Youden's approach. The decision limit and detection capability values in the milk were achieved from 101.9 to 113.5 μg/kg and from 114.4 to 135.4 μg/kg, respectively, depending on the target sulfonamide drug. Finally, the optimized protocol was successfully applied to commercial milk samples and human breast milk.  相似文献   
4.
The current study provides a way of extraction for both active NSO and WSE from Nigella sativa seeds using 98% methanol. About 1?kg of ground seeds was macerated by 1:2.5 w/v (g/mL) for 72?hours. After rotary evaporation and 7 days of continuous drying and chilling at 50 and 4?°C, NSO and WSE were obtained at the same instant. Solubility tests of 24 solvents and 11 thin layer chromatographic analyses while 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging assay of NSO (73.66) , WSE (33.32) and NSO?+?WSE (78.22) against ascorbic acid (IC50?=?4.28?mg/mL) was performed. WSE was found to be highly soluble in water and 5% NaOH exhibiting the same Rf value of 0.95 for EtOH:DMSO (9:1) against the honey. WSE has revealed more than twofold higher anti-oxidant activity than others. Formulation of WSE with Tualang honey may provide better targeted hydrophilic drug delivery systems.  相似文献   
5.
This study presents a simple and green dispersive micro‐solid phase extraction method for preconcentration of acidic quinolones from honey prior to high performance liquid chromatography determination. A two‐dimensional nanostructured zinc‐aluminum layered double hydroxide was synthesized and used as the sorbent for dispersive micro‐solid phase extraction. Its different characteristics from conventional sorbents is that it is dissolvable in acidic solution (pH < 4). After the extraction, the analyte elution step was omitted and thus the use of organic solvents was avoided. The key parameters influencing the extraction efficiency such as the amount of sorbent, pH of sample solution, vortex time, type and volume of acidic solution were investigated and optimized. The method exhibited low limits of detection (3.0?5.0 ng/g), good linearity (10?2000 ng/g) with coefficients of determinations higher than 0.9991, acceptable precision (RSD<9.1%) and accuracy (RE<5.8%). The proposed method is fast, efficient, eco‐friendly, and suitable for the determination of acidic quinolones in honey samples.  相似文献   
6.
Dan‐Huang‐Qu‐Yu capsule, a Chinese herbal medicine compound preparation, is widely used for chronic pelvic inflammatory disease. In this study, a rapid, selective, and sensitive microwave‐assisted extraction ultra‐high‐performance liquid chromatography‐Q Exactive quadrupole‐orbitrap high‐resolution mass spectrometry method was developed for analyzing its chemical compositions. A total of 85 compounds, including 22 flavonoids, 8 terpenoids, 5 quinones, 5 phthaleolactone, 23 organic acids, and 22 other compounds were identified from Dan‐Huang‐Qu‐Yu capsule. Among them, 35 major compounds were unambiguously detected by comparing them with reference standards and selected as quality control markers, which were simultaneously determined in Dan‐Huang‐Qu‐Yu capsule. The established method was successfully validated and applied for simultaneous determination of 35 bioactive compounds in Dan‐Huang‐Qu‐Yu capsule from ten sample batches. The quantitative data of the analytes were analyzed by principal component analysis for quality assessment of Dan‐Huang‐Qu‐Yu capsule. Six compounds (e.g., astragaloside IV, salvianolic acid B, ellagic acid, chlorogenic acid, N‐butylidenephthalide, and luteolin) were screened out and regarded as chemical markers for quality control of Dan‐Huang‐Qu‐Yu capsule. The established method has been proved to be a novel and useful tool for rapid research of Dan‐Huang‐Qu‐Yu capsule. This research will provide reference for the scientific research of traditional Chinese medicines.  相似文献   
7.
A novel solid‐phase microextraction Arrow was used to separate volatile organic compounds from soy sauce, and the results were verified by using gas chromatography with mass spectrometry. Solid‐phase microextraction Arrow was optimized in terms of three extraction conditions: type of fiber used (polydimethylsiloxane, polyacrylate, carbon wide range/polydimethylsiloxane, and divinylbenzene/polydimethylsiloxane), extraction temperature (40, 50, and 60°C), and extraction time (10, 30, and 60 min). The optimal solid‐phase microextraction Arrow conditions were as follows: type of fiber = polyacrylate, extraction time = 60 min, and extraction temperature = 50°C. Under the optimized conditions, the solid‐phase microextraction Arrow was compared with conventional solid‐phase microextraction to determine extraction yields. The solid‐phase microextraction Arrow yielded 6–42‐fold higher levels than in solid‐phase microextraction for all 21 volatile organic compounds detected in soy sauce due to the larger sorption phase volume. The findings of this study can provide practical guidelines for solid‐phase microextraction Arrow applications in food matrixes by providing analytical methods for volatile organic compounds.  相似文献   
8.
Scandium and its compounds are used in many modern industrial fields due to its unique chemical and physical properties. It is mainly recovered from residues and wastes in the production of other metals. The exploitation of the ores and wastes could contaminate water and soil creating environmental problems. This paper discusses recent developments and tendencies in scandium separation, purification and preconcentration from different wastes, residues, environmental samples as well as in the production of radiopharmaceuticals for nuclear medicine, both in the laboratory and on the industrial scale. The period reviewed here mainly includes publications that have appeared, since 2010.  相似文献   
9.
建立了水产品中11种海洋生物毒素的高效液相色谱-四极杆/静电场轨道阱高分辨质谱(HPLC-Q-Orbitrap HRMS)检测方法。该方法采用分级提取原理,结合分散固相萃取技术(dSPE)和载体辅助液液萃取技术(SLLE),建立了对亲水性及亲脂性海洋生物毒素的"一站式"提取净化体系。在优化条件下,11种毒素在一定质量浓度范围内具有良好的线性关系,相关系数(r)均大于0.99。该方法对11种毒素的检出限为1~10μg/kg,定量下限为2~20μg/kg,加标回收率为55.6%~122%,相对标准偏差为5.4%~16%。方法快速高效,可操作性强,解决了不同理化性质的海洋生物毒素的通用性检测问题,可满足水产品中海洋生物毒素的快速筛查要求。  相似文献   
10.
A homogeneous liquid‐liquid extraction performed in narrow tube coupled to in–syringe‐dispersive liquid‐liquid microextraction based on deep eutectic solvent has been developed for the extraction of six herbicides from tea samples. In this method, sodium chloride as a separation agent is filled into the narrow tube and the tea sample is placed on top of the salt. Then a mixture of deionized water and deep eutectic solvent (water miscible) is passed through the tube. In this procedure, the deep eutectic solvent is realized as tiny droplets in contact with salt. By passing the droplets from the tea layer placed on the salt layer, the analytes are extracted into them. After collecting the solvent as separated layer, it is mixed with another deep eutectic solvent (choline chloride/butyric acid) and the mixture is dispersed into deionized water placed in a syringe. After adding acetonitrile to break up the cloudy state, the collected organic phase is injected into gas chromatography‐mass spectrometry. Under optimal conditions, limits of detection and quantification in the ranges of 2.6–8.4 and 9.7–29 ng/kg, respectively, were obtained. The extraction recoveries and enrichment factors in the ranges of 70–89% and 350–445 were obtained, respectively.  相似文献   
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