共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
研究了正辛基-L-羟基脯氨酸萃取苯丙氨酸的性能和机理, 详细考察了起始氨基酸的浓度、萃取剂的浓度、酸度、铜离子的浓度、温度等因素分别对D-和L-苯丙氨酸萃取性能的影响. 随着起始氨基酸pH值的增大, 萃取分配比D也增大, 对映体分离系数α可以达到2. 萃取反应为吸热反应, 升高温度有利于反应的进行. 表征了萃合物的组成, 推测萃合物的结构为1∶1∶1型的三元配合物. 研究结果为苯丙氨酸的萃取拆分提供了理论依据. 相似文献
3.
4.
N,N,N‘,N’—四己基丙二酰胺从硝酸介质中萃取铀(Ⅵ) 总被引:2,自引:1,他引:2
以甲苯为稀释剂研究了N,N,N',N'-四己基两二酰胺从硝酸介质中萃取硝酸和铀(Ⅵ)的性能.考察了水相硝酸浓度、李取剂浓度、硝酸钠浓度以及温度对萃取分配比的影响,确定了萃合物的组成.借助红外光谱分析了萃合物的结构.求得了萃取硝酸和硝酸铀酰的平衡常数及反应的热力学焓变.与N,N,N',N'-四丁基丙二酰胺萃取铀的性能比较,发现烷基链长的增加减少了三相生成的倾向,但酰胺的萃取能力却下降. 相似文献
5.
6.
7.
8.
本文合成新手性配体正十二烷基-L-羟基脯氨酸,研究手性配体正十二烷基-L-羟基脯氨酸与Cu髤配位萃取拆分苯丙氨酸的性能和机理,考察起始氨基酸浓度、配位铜离子浓度、萃取剂浓度、溶液pH值及温度等因素分别对D-和L-苯丙氨酸萃取性能的影响,萃取剂对D-苯丙氨酸的识别能力强。利用多种手段对萃合物的组成进行表征,推测萃合物的结构为1∶1∶1型三元配合物。对比发现:该萃取剂配位萃取拆分苯丙氨酸性能优于正辛基-L-羟基脯氨酸,空间位阻效应反而对拆分有利。 相似文献
9.
10.
合成了四取代双酰胺萃取剂N,N,N',N'-四丁基丁二酰胺(TBSA),并对萃取剂的结构进行了表征.研究了其萃取Pr(Ⅲ)的性能,考察了硝酸浓度、萃取剂浓度、硝酸锂浓度以及温度等对萃取分配比的影响.萃取反应在298K时,TBSA以甲苯为稀释剂时的热力学焓变为-12.83 kJ/mol.萃合物的组成结构为Pr(NO3)3·3TBSA. 相似文献
11.
Wu Ming-Hong 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(1):195-197
Extraction of uranium(VI) from nitric acid solutions with N-octanoylpyrrolidine(OPOD) in a series of diluents has been studied. The dependence of the extractiondistribution ratios on the concentrations of aqueous nitric acid, extractant,salting-out agent and the temperature was investigated. The experimental resultsshowed that the extracting capacity of OPOD in different diluents increasesin the order: chloroform, carbon tetrachloride, 1,2-dichloroethane, n-dodecane,n-octane, cyclohexane, toluene and benzene. This can not be explained onlyon the theory of polarity of the diluents. The interaction between extractantand the extracted complex and diluent is discussed. 相似文献
12.
V. A. Doroshchuk N. A. Gonta M. V. Drozdova S. A. Kulichenko 《Journal of Analytical Chemistry》2009,64(10):1054-1058
The micellar extraction of furosemide by the nonionic surfactant (NS) Triton X-100 at the cloud point was studied; it was
performed in a conventional heating mode and upon induction with phenol. It was shown that the quantitative recovery of the
preparation was attained using hydrophobic micellar phases of NS modified with phenol. A procedure was developed for determining
furosemide in urine by reversed-phase HPLC with preconcentration by micellar extraction in the presence of phenol. The preconcentration
ratio was 80 and the detection limit for furosemide, 3 mg/L. The procedure was used to analyze urine samples by the standard
addition method. 相似文献
13.
Qi H Lv J Li B 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):874-878
In this paper, a simple flow-injection chemiluminescence (CL) system combined with on-line solid-phase extraction is presented to determine phenol. This method is based on the enhancement effect of phenol on the luminol-K3Fe(CN)6 CL system. The solid-phase extraction promised the high sensitivity and improved selectivity of CL detection. With the calibration range from 4.7 ng l-1 to 470 ng l-1 phenol concentration, the proposed method was applied to analyzing phenol in water samples and the obtained results were validated by the standard method. The detection limit was determined as 0.66 ng l-1. The relative standard deviation was 1.5% for determining 4.7 ng l-1 phenol standard (n=7). 相似文献
14.
15.
建立了亚临界水萃取-高效液相色谱同时测定聚碳酸酯(PC)水杯中双酚A和苯酚迁移量的方法。选择萃取温度120 ℃、萃取压力6.89 MPa(1000 psi)、静态萃取时间1 h、萃取1次对11种样品进行测定。双酚A的迁移量为6.81~11.16 μg/g。5种样品中未检出苯酚,其余样品中苯酚迁移量为3.25~6.08 μg/g。在优化的测定条件下,双酚A和苯酚在8 min内达到基线分离。双酚A和苯酚分别在0.05~20 mg/L和0.02~20 mg/L范围内线性关系良好,相关系数(r)均大于0.9997,检出限分别为7.6 μg/L和2.0 μg/L。日内及日间的重复性(以RSD计)分别小于5.21%及11.63%。传统的浸提法结果表明长时间浸提会使PC材料发生微弱水解。相比传统的浸提法,该方法的萃取效率提高了49~106倍。该方法简便、快速、环保,可用来测定PC水杯中双酚A和苯酚的迁移量。 相似文献
16.
17.
建立了酚法提取-二维液相色谱分离-高分辨质谱分析水稻叶片蛋白质组的方法。水稻叶片蛋白质经过酚法提取,酶解肽段脱盐后用离线反相-反相二维液相色谱分离,然后用线性离子阱/静电场轨道阱组合式高分辨质谱分析,共鉴定到2712种蛋白质。比较了液相色谱分离系统(一维液相色谱与二维液相色谱)和水稻叶片蛋白质提取方法(酚法、十二烷基硫酸钠法(SDS法)和三氯乙酸/丙酮法(TCA/丙酮法))对鉴定蛋白质数量的影响,结果表明:在二维液相色谱条件下,酚法、SDS法和TCA/丙酮法鉴定到的蛋白质数目为2712、2415和1914,分别是一维液相色谱条件下鉴定到的蛋白质数目的2.7、2.5和1.9倍。二维液相色谱条件下,酚法鉴定到的蛋白质数目比SDS法和TCA/丙酮法分别多297和798。与SDS法和TCA/丙酮法相比,酚法不但鉴定到的蛋白质数量多,而且能够鉴定到一些极端蛋白质,如酸性、碱性及高等电点的蛋白质。此外,对二维液相色谱条件下3种蛋白质提取方法提取到的蛋白质进行生物学功能分类,发现3种方法鉴定到的蛋白质的功能存在互补性,但酚法鉴定到的蛋白质功能种类最多。该法为水稻蛋白质组学研究提供了技术支撑,同时也为其他作物的蛋白质组学研究技术提供重要的借鉴。 相似文献
18.
采用电动力学技术修复苯酚污染的粘性土壤,研究了苯酚的吸附特性,以及粘土中苯酚的最佳萃取剂和萃取条件,并讨论了不同pH、含水率、电场强度及不同添加物条件下苯酚的迁移特性. 实验得出,苯酚的吸附符合Freundlich等温式,最大吸附量362 mg·kg-1;用三氯甲烷做萃取剂,超声波20 min加恒温震荡30 min,从土壤中提取苯酚,萃取率可达到94.3%;土壤电动力学过程中苯酚向阳极迁移并在距离阳极0 ~ 6 cm处富集. 在pH值8.16,含水率为40%,电场强度为2 V·cm-1条件下,阳极添加0.1 mol·L-1 NaOH溶液,并向阴极添加0.05 mol·L-1 LAS溶液,苯酚的迁移效果达到最佳,在距阳极0 cm和6 cm处苯酚富集倍数分别达到139.0%和133.7%. 相似文献
19.
Uptake of phenol by graphite, and regeneration by methanol extraction, was measured to evaluate irreversible adsorption of phenols to carbon surfaces. The emphasis of this work was to identify the role of oxidative coupling, which has been invoked to explain irreversible phenol sorption by activated carbons. Graphite was chosen as a model carbon surface to eliminate potentially confounding effects of microporosity present in other types of carbonaceous sorbents. The isotherm data were well described by the Langmuir-Freundlich isotherm from pH 3 to 9. At pH 12, measured uptakes were higher than expected based on model predictions, suggesting the occurrence of an adsorption mechanism besides physisorption. One oxidative coupling product, 2,2'-dihydroxybiphenyl, was obtained exclusively after adsorption at pH values above 7, and appeared both in aqueous solution and in the methanol regenerant solution. The fraction of total uptake that was not recoverable by methanol extraction decreased with increasing phenol concentration in solution, suggesting preferential sorption by high-energy sites. However, absolute irreversible adsorption increased with phenol concentration in solution. Both fractional irreversible adsorption and 2,2'-dihydroxybiphenyl oxidative coupling product recovery as a function of pH and contact time demonstrated that irreversible sorption of phenol by graphite could not be explained by an oxidative coupling mechanism alone. 相似文献
20.
采用固相萃取(SPE)小柱固相萃取,建立了生活饮用水中2-氯苯酚和2-甲苯酚的气相色谱检测方法。用盐酸调节水样至p H 5.0,用SPE小柱固相萃取后以乙酸乙酯洗脱,以CD-5色谱柱进行分离,氢火焰离子化检测器检测2-氯苯酚和2-甲苯酚的含量。2-氯苯酚和2-甲苯酚的质量浓度在2.00~40.0μg/L范围内与色谱峰面积线性关系良好,检出限分别为0.03,0.04μg/L;加标回收率分别为87.2%~93.9%,89.0%~94.8%;测定结果的相对标准偏差均小于2%(n=7)。该方法具有检出限低、操作简便等优点,适用于生活饮用水中2-氯苯酚和2-甲苯酚的监测分析。 相似文献