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1.
微波辅助萃取及其联用技术在有机污染物分析中的应用   总被引:1,自引:0,他引:1  
微波萃取已经发展成为一种常用的快速、高效、污染小的样品的前处理技术。结合有机污染物的气相色谱测定方法,对近年微波萃取技术的研究进展进行了总结,并指出微波与固相微萃取、微固相萃取、顶空萃取、膜分离方法、蒸汽蒸馏萃取、微波催化和消解等方法的联用技术将是微波萃取的重要发展方向。  相似文献   

2.
磁固相萃取是一种基于磁性材料而发展起来的新型样品前处理技术,是目前样品预处理领域的研究热点,其中有关磁性吸附材料的研究是该技术的关键。离子液体是一种由有机阳离子和有机或无机阴离子构成的液态有机盐类,因挥发性低,化学及热稳定性好以及对有机物、无机物具有良好的溶解性而成为富集水溶液中有机污染物和重金属离子的新型吸附材料,但将其用于磁固相萃取的研究尚处于起步阶段。本文总结了磁性富集技术中所用的离子液体,并将目前基于离子液体的磁性富集技术归纳为基于离子液体功能化磁性微球的磁固相萃取、混合半胶束磁固相萃取、离子液体参与的双磁微萃取3类。并综述了基于离子液体的磁性富集技术在环境、食品及生物样品前处理方面的应用研究,简要总结了根据待测物质选择基于离子液体的磁性富集技术的原则,并对基于离子液体的磁性富集技术未来的发展方向进行了展望。  相似文献   

3.
魏嘉勋  陈文 《化学通报》2022,85(3):331-340,296
全氟辛烷磺酸及其盐(PFOS)广泛应用于纺织品、皮革、家具等上千种工业和日用生活用品的生产中,由于具有多脏器毒性,被列为继多氯联苯、有机氯农药和二噁英之后的又一种新型持久性有机污染物。因此,PFOS的准确监测对环境PFOS污染的预警预报具有重要的意义。PFOS在样品中含量低,因此样品前处理技术是准确分析的关键。本文对目前应用于水样中PFOS分析的前处理技术如液-液萃取、固相萃取、磁性固相萃取、毛细管整体柱固相萃取和固相微萃取进行了概述,并对它们的特点进行了评述,重点阐述了固相微萃取技术的研究进展,并对近年应用于环境水样前处理PFOS固相微萃取剂的研究进展进行了综述,对新型萃取剂的研究提出展望。  相似文献   

4.
亚临界水萃取技术应用于环境样品预处理的研究   总被引:1,自引:0,他引:1  
对近几年来亚临界水萃取(Sub-critical water extraction,SCWE)技术的研究进行了综述,介绍了亚临界水萃取技术的原理、特点及其在环境分析中的应用。与传统的样品预处理方法和一些新的样品预处理技术(如微波辅助萃取)相比,SCWE可以不使用有机溶剂,对环境造成的污染较小,是一种绿色的样品预处理技术。SCWE在萃取能力、回收率、精密度等方面具有相当的可靠性。方法具有较高的选择性分离预富集某些有机污染物(如多环芳烃等)的特点(引述文献22篇)。  相似文献   

5.
液相微萃取技术的研究进展   总被引:43,自引:8,他引:35  
赵汝松  徐晓白  刘秀芬 《分析化学》2004,32(9):1246-1251
液相微萃取是近年来发展起来的一种新型的样品前处理技术,该技术集采样、萃取和浓缩于一体,需要有机溶剂量非常少,是一种环境友好的萃取技术,在国内尚未广泛应用。本文综述了液相微萃取的方式、原理、影响因素和应用,引用文献30篇。  相似文献   

6.
超临界流体萃取对大气飘尘中有机污染物的分析   总被引:11,自引:0,他引:11  
采用超临界流体萃取与气相色谱/质谱联用技术对兰州市大气飘尘中有机污染物进行了测定。实验考察了对强致癌性化合物多环芳烃类萃取的最佳条件,在26.0MPa,80℃下,0.5mL甲醇做改性剂,用CO2作为超临界萃取介质,静态萃取10min后再以0.5mL/min的流速动态萃取30min,对实际样品进行了定性定量分析,共检测出69种有机污染物,该方法简便,快速,适合于飘尘中有机污染物的测定。  相似文献   

7.
浊点萃取技术的应用   总被引:5,自引:0,他引:5  
浊点萃取是近年发展起来的一种新兴的萃取技术。重点阐述了浊点萃取在环境样品、生物样品和食品工业分析中的应用,总结了浊点萃取技术的优点,指出了存在的问题,探讨了该技术的发展前景。  相似文献   

8.
超声波强化四氯乙烯溶剂法脱除煤中有机硫的研究   总被引:12,自引:2,他引:10  
研究了超声波辐射强化四氯乙烯溶剂萃取法脱除煤炭有机硫的技术。采用单因子法考察了煤的粒度、煤浆浓度、超声辐射萃取反应温度、超声辐射萃取反应时间、超声辐射功率等因素对脱硫率的影响,优选出了超声辐射四氯乙烯溶剂萃取法脱除煤样中有机硫的最佳工艺条件为:用四氯乙烯作溶剂,环境压力下,煤浆浓度为10mL/g、煤粒度为0.074mm、萃取反应时间120min,萃取反应温度90℃,超声辐射功率500W,超声辐射频率40kHZ,煤样有机硫的脱硫率可达到59.1%。研究结果表明:超声波辐射下四氯乙烯溶剂萃取是脱除煤中有机硫的一种有效方法。与四氯乙烯溶剂萃取法相比,能够显著的缩短反应时间,提高脱硫率。  相似文献   

9.
固相微萃取技术与环境样品前处理   总被引:28,自引:0,他引:28  
固相微萃取技术是80 年代末发展起来的一项新型的无溶剂化环境样品前处理技术, 它主要与气相色谱和高效液相色谱联用, 能快速和有效地分析环境样品中的痕量有机污染物。技术从出现至今主要在萃取装置(萃取纤维涂层)、萃取方式及后序分析仪器上有较大的发展和变化, 这使得技术的应用范围不断拓宽。通过对现有文献的总结, 本文还提出了固相微萃取技术今后的发展趋势。  相似文献   

10.
利用顶空固相微萃取.气相色谱联用技术(HS-SPME-GC),以100μm聚二甲基硅氧烷(PDMS)萃取头分析柠檬酸中的5种有机挥发性杂质,并对萃取温度、吸附时间、解吸时间和盐析作用进行了研究。结果显示,该方法具有较好的精密度和较宽的线性范围,样品加标回收率92.4%-103.5%,检出限完全满足美国药典USP23对柠檬酸中有机挥发性杂质的限量要求。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.  相似文献   

15.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

16.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

17.
潘素娟  全灿  周俊波 《化学通报》2014,77(12):1165-1170
测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。  相似文献   

18.
The thermodynamics of adsorption has been studied of hydrolyzed modified polyacrylnitrile (HMP) in water solutions with a concentration ranging from 0.25 g/l to 2.00 g/l on bleached sulphate and unbleached and bleached sulphite celluloses at temperatures of 0, 20, 40, and 60 C.It has been established that with the rise in temperature, the amount of adsorbed polymer —(HMP) decreases. The values of the enthalpy change are negative and show a linear decrease with the increase in the amount of adsorbed polymer. The adsorption equilibrium is defined by the logarithmic isotherm of Tjumkin, valid for uniform heterogeneous surfaces.With the increase in the amount of adsorbed HMP the values of the entropy change become negative and linearly decrease. A compensation effect has been noticed which results from the simultaneous action of the entropy and energy factors.The values of the change of the chemical potential for the three types of cellulose are negative and linearly decrease with the increase in the amount of adsorbed HMP and with the rise in temperature.  相似文献   

19.
The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m2g-1 instead of aerosil with one of 175 m2g-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

20.
栽培草莓品种果实香气特性研究   总被引:15,自引:0,他引:15  
通过对4个不同栽培草莓(Fragaria ananassa Duch.)品种果实糖和氨基酸测定及香气的GC-MS分析,结果表明:不同品种间氨基酸和糖含量不同,氨基酸含量由高到低依次为丰香、瓦尔达、哈达和全明星;哈达、丰香、全明星和瓦尔达4个品种果实分别检测出39、46、37和44种香气成分,各占总峰面积98.52%、99.15%、98.77%和95.4l%,检测成分的多少与氨基酸总量显著正相关,相关系数为0.967;哈达有5种独有的成分,丰香有9种独有的成分,全明星有3种独有的成分,瓦尔达有2种独有的成分,4个品种共有的成分有19种。  相似文献   

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