基于综合素质培养的化学基础综合实验设计——以谷物中生育酚的测定实验为例

设计了题为“分散液相微萃取-高效液相色谱法测定谷物中生育酚”的综合实验，并应用于化学基础综合实验教学中。本实验以新型样品前处理技术——分散液相微萃取技术为基础，通过查阅文献，确定了合适的萃取模式、分散策略、萃取装置、萃取效果评价指标、HPLC分离分析条件等实验内容。实验设计结合了新颖的科研内容，能引起学生主动探索未知的兴趣，是对基础化学实验操作技能的强化，有利于提高学生的创新能力和综合素质。     

分散液相微萃取-高效液相色谱法测定水中α-萘酚和β-萘酚

以氯苯为萃取剂,丙酮为分散剂,采用分散液相微萃取-液相色谱联用技术对水体中的α-萘酚和β-萘酚进行分析,优化了实验条件。该方法对α-萘酚和β-萘酚的线性范围分别为1.5～50μg/L和1.0～50μg/L,检出限分别为0.9μg/L和0.5μg/L,6次重复测定的相对标准偏差分别为3.3%和1.5%。方法应用于自来水、地下水和湖水样品的分析测定,回收率在91.3%～101.0%之间。     

分散液相微萃取-高效液相色谱法同时测定尿样中多环芳烃四种代谢产物

本研究建立了同时测定尿样中多环芳烃的四种代谢产物1-羟基芘、萘、1-萘酚和2-萘酚的分散液相微萃取-高效液相色谱法。确定了最佳的色谱条件,并对萃取剂种类及用量、分散剂种类及用量、萃取时间、加盐量、样品pH和挥干时间等条件进行了优化。在最佳的实验条件下,建立了四种组分的工作曲线,线性相关系数均达到0.9999,线性范围可达103,检出限(S/N=3)为0.06～0.3ng/mL,样品加标平均回收率为95.4%～105%,相对标准偏差为2.4%～3.5%。     

中药材成分有机溶剂与离子液体分散液相微萃取方法的比较及其机理探讨

研究了离子液体分散液相微萃取(ILDLPME)机理;比较了ILDLPME和有机溶剂分散液相微萃取(OSDLPME)在测定蒽醌类化合物中的异同;建立了分散液相微萃取-高效液相色谱法测定药材中6种游离蒽醌类化合物(芦荟大黄素、大黄酸、丹蒽醌、大黄素、大黄酚和大黄素甲醚)含量的方法。在优化的实验条件下,OSDLPME和ILDLPME对6种分析物的富集倍数分别为101～230和76～181;6种分析物的检出限分别在20～200ng/L和40～400ng/L之间;精密度(RSD)分别在3.1%～10.0%和1.3%～7.0%之间;4种中药材中分析物的回收率在81.7%～110.7%和81.9%～110.8%之间。离子液体在水中分散的同时进行有序排列,形成分子有序组合体,对分析物进行萃取。ILDLPME达平衡时间更快,精密度更高,方法更简便;OSDLPME浓缩倍数更高,检出限更低;两种方法对中药样品中游离蒽醌类化合物含量测定结果无显著性差异。     

分散液相微萃取技术研究进展

分散液相微萃取是最近发展起来的一种新型样品前处理技术,该方法操作简单、成本低、富集效率高、所需有机溶剂用量极少,是一种环境友好的液相微萃取新技术.与悬滴液相微萃取和中空纤维液相微萃取相比,萃取时间大为缩短.分散液相微萃取可与气相色谱、液相色谱和原子吸收分光光度计等仪器联用,并已在环境样品、食品样品分析中得到了较广泛的应用.本文对分散液相微萃取的基本原理、影响富集效率的因素和目前的应用研究进展进行了评述.     

固相萃取-分散液液微萃取-高效液相色谱法测定椰子汁中酸性植物激素

本文通过固相萃取结合分子络合物-分散液液微萃取,与高效液相色谱联用,建立了一种测定椰子汁中酸性植物激素的新方法。选择了几种典型酸性植物激素吲哚乙酸、水杨酸、脱落酸和吲哚丁酸作为分析物,考察了该方法的萃取性能。在固相萃取与分子络合物-分散液液微萃取联用模式中,椰子汁中分析物首先吸附在C18萃取材料上,待解吸完成后,解吸液又可用作分散液液微萃取的分散剂,大大简化了萃取步骤。该方法的富集倍数可达319～478倍,线性关系良好,具有良好的精密度和准确度,有望用于植物激素的检测。     

分散液相微萃取-高效液相色谱法测定水中丙溴磷农药

应用分散液相微萃取(DLLME)技术,建立了水中丙溴磷农药的高效液相色谱(HPLC)分析方法。考察了萃取剂、分散剂、萃取剂体积、分散剂体积、时间、盐度和pH等因素对分散液相微萃取的影响,并确定了最佳萃取条件为:15μL三氯乙烷(萃取剂)和700μL乙腈(分散剂),混匀后,加入水样,室温静置2min,以3000r/min离心2min,吸取3μL沉积相,进行HPLC分析。在此优化条件下,富集倍数达到270,检出限为2μg/L,相对标准偏差(RSD)为1.4%～6.1%(n=6);标准加入回收率为81.9%～118%。本方法操作简单,成本低,结果令人满意。     

液相微萃取-高效液相色谱法测定尿样中的利多卡因

应用液相微萃取与高效液相色谱联用技术快速分析尿样中的利多卡因。考察了萃取溶剂、体积、萃取时间及料液pH值对液相微萃取的影响,建立了液相微萃取与高效液相色谱联用技术分析尿样中利多卡因的方法。优化的实验条件为：料液pH值12．0,萃取溶剂为5μL邻苯二甲酸二丁醅,萃取时间40min,搅拌速度80r／min。方法的线性范围为0．2-5mg／L;检出限为0．1mg／L;相对标准偏差小于6．3％。通过液相微萃取后,能有效地去除检测尿样中利多卡因的干扰物质,获得了较高的选择性。该方法简便、快速、灵敏、消耗有机溶剂少,是尿样中利多卡因检测的一种有效方法。     

分散液相微萃取/高效液相色谱法同时测定啤酒中3种酮类老化物质

建立了分散液相微萃取(DLLME)/高效液相色谱(HPLC)同时测定啤酒中双乙酰、2,3-戊二酮和β-大马酮3种主要酮类老化物质的方法.确定了双乙酰和2,3-戊二酮的衍生化反应条件和3种目标组分同时检测的高效液相色谱条件,在15 min内实现了对3种酮类老化物质的分离和检测;优化了分徽液相徽萃取的实验条件,使3种目标组...     

化学工业出版社化学专业图书推荐

液相微萃取本书对新兴样品前处理方法—液相微萃取技术作了全面介绍,详细阐述了液相微萃取技术的基本理论、操作模式、方法原理、影响因素、实验装置、操作条件及其优化、定量方法评价等内容;并对液相微萃取技术在环境、药物、食品、临床等领域的分析应用进行了概述。本书综合了液相微萃取自建立以来国内外的重要成果和新技术,兼具理论性和实用性.     

Regioselectivity of olefin oxidation by iodosobenzene catalyzed by metalloporphyrins : control by the catalyst

The regioselectivity of the oxidation of three monosubstituted olefins, 6-phenoxyhex-1-ene, hex-1-ene and styrene, by iodosobenzene in the presence of various Fe-, Mn- or Cr-tetraaryl-porphyrins, was studied. It was found that, besides epoxides, known products from such systems, allylic alcohols and aldehydes were formed, the latter not being derived from the corresponding epoxides. The relative importance of these reactions greatly depends upon both the metal and porphyrin constituents of the catalyst. More particularly, the competition between epoxidation and allylic hydroxylation can be efficiently controlled by non-bonded interactions between the olefin and porphyrin substituents. No hydroxylation of the aromatic rings and no oxidative dealkylation of the ether function was detected.     

Oxidation of 1,4-dimethylcyclohexane by perchloric acid catalyzed by polyphenylferrosiloxane

The reaction of oxidation of 1,4-dimethylcyclohexane (DMCH) by perchloric acid at ～20 °C catalyzed by polyphenylferrosiloxane has been found. The chromatographic analysis has revealed the formation of several products, including the tertiary alcohol with 100% retention of the configuration of the initial configuration. The specific feature of the process is the following: along with the high stereospecific formation of the tertiary alcohol,cis-trans isomerization in the starting 1,4-DMCH is observed. The data obtained are discussed on the basis of the mechanism, including the formation of a ferryl intermediate with the subsequent transfer of the oxygen atom to the tertiary C?H bond of 1,4-DMCH through the intermediate complex with the five-coordinated carbon.     

Production of Enzymes by Plant Cells Immobilized by Sol-Gel Silica

Ajuga reptans cells are cultivated and used for production of invertase. These plant cells are immobilized by a sol-gel SiO₂ membrane, which is built up directly on the cell surface by exposure to a gaseous flow of silicon alcoxide precursors. The immobilization modifies the metabolic activity of cells, resulting in a 40-fold increase in invertase production with respect of free cells. Results concerning total release of proteins, cell growth and produced invertase activity are discussed, considering the absence of breeding, induced by SiO₂ immobilization, the prominent factor promoting the observed exceptional increase in invertase productivity.     

Desymmetrization of Dicationic Diboranes by Isomerization Catalyzed by a Nucleophile

Cationic monoboranes exhibit a rich chemistry. By constrast, only a few cationic diboranes are known, that all are symmetrically substituted. In this work, the first unsymmetrically substituted dicationic diboranes, featuring sp²–sp²‐hybridized boron atoms, are reported. The compounds are formed by intramolecular rearrangement from preceding isomeric symmetrically substituted dicationic diboranes, a process that is catalyzed by nucleophiles. From the temperature‐dependence of the isomerization rate, activation parameters for this unprecedented rearrangement are derived. The difference in fluoride ion affinity between the two boron atoms and the bonding situation in these unique unsymmetrical dicationic diboranes are evaluated.     

Synthesis of arylaliphatic chlorosilanes by alkylation of aromatic compounds by alkenylchlorosilanes

Conclusions In combination with HCl or H₂O, EtAlCl₂ is an active catalyst for alkylation of aromatic compounds by alkenylchlorosilanes, and compounds of boron, titanium, and tin are inactive in this reaction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1639–1641, July, 1985.