離子液體在色譜中的應用

1、離子液體在色譜中的應用第1頁，共16頁，2022年，5月20日，10點56分，星期五 高效液相色譜法包括正相高效液相色譜法和反相高效液相色譜法。正相高效液相色譜法中流動相的極性小于固定相的極性，也就是以及性鍵合相為固定相（常以氨基、氰基鍵合相等作為固定相）。反相高效液相色譜法中流動相的極性大于固定相的極性，也就是以非極性鍵合相為固定相（常以十八硅烷C18、辛烷C8、甲基C1、苯基等作為固定相）。 離子對試劑是由強親水離子形成，反作用于樣品分子中的中性離心子對。因此，可用于同時分離帶電分子和非帶電分子。一般適用所有色譜固定相，流動相含水至少達10，否則就有產(chǎn)生沉淀的危險（特別是在使用乙腈的情況下

2、）。當使用長鏈的離子對試劑時，如十六烷基硫酸銨或十二烷基硫酸鈉，色譜柱將選用反相色譜柱。2第2頁，共16頁，2022年，5月20日，10點56分，星期五 抗衡離子：在離子型聚合反應中，存在于增長鏈末端活性離子附近的相反電性離子。 洗脫與洗脫劑：在洗脫色譜操作中，流動相攜帶待測組分在色譜柱內(nèi)向錢移動并流出色譜柱的過程稱為洗脫。所用流動相稱為洗脫劑。3第3頁，共16頁，2022年，5月20日，10點56分，星期五2.反相高效液相色譜法中離子液體作為流動相添加劑對兒茶酚胺保留值的影響3.離子交換色譜法和反相高效液相色譜法分析選定的離子液體陽離子4.1-烷基3-甲基咪唑離子液體作為洗脫劑對液相色譜法分

3、離麻黃素的影響1.反相液相色譜法測定選擇性室溫離子液體陽離子5.離子液體雙水相體系，高效液相色譜法測定鴉片生物堿的樣品前處理過程4第4頁，共16頁，2022年，5月20日，10點56分，星期五6.使用四氟硼酸咪唑離子液體抑制液相色譜分析中游離硅羥基的不利影響7.離子液體在液體色譜法中減少硅羥基的相互作用 8.基于離子液體的液相微萃取-高效液相色譜法測定水中有機磷農(nóng)藥9.液體作為高效液相色譜分析的添加劑：分析胺和離子液體的相互作用機制10.離子液體液液萃取-高效液相色譜測定水中酚類化合物5第5頁，共16頁，2022年，5月20日，10點56分，星期五1.Reversed-phase liquid

4、 chromatographic method for the determination of selected room-temperature ionic liquid cations AbstractThe separation of selected 1-alkyl- and 1-aryl-3-methylimidazolium-based room temperature ionic liquid cations has been performed using reversed-phase high-performance liquid chromatography with e

5、lectrospray ionization mass detection. The RP-HPLC method development started with the selection of a column taking into account especially the resolution of low molecular congeners of the selected group. Mobile phase composition was optimized for peak resolution, sensitivity and high reproducibilit

6、y of retention values. The results of the method development were applied to the determination of exemplary ionic liquid species present in the medium used in cytotoxicity studies.6第6頁，共16頁，2022年，5月20日，10點56分，星期五2.Effect of Ionic Liquids as Mobile Phase Additives on Retention of Catecholamines in Re

7、versed-Phase High-Performance Liquid Chromatography Abstract Ionic liquids or room temperature ionic liquids have been widely investigated as new solvents for catalysis in the past several years. Because of some special properties of ionic liquids, interest of using them in different chemical proces

8、ses is increasing. This work reports on the use of 1-alkyl-3-methylimidazolium salts and N-butyl-pyridinium salts as new mobile phase additives for separation of catecholamines in reversed-phase high-performance liquid chromatography. The good separation is achieved by using these additives. Differe

9、nt pH values of the mobile phase, concentration of ionic liquids, and different alkyl substituents on the cations or different counterion of ionic liquids were investigated. The separation mechanism involves molecular interactions between ionic liquids and catecholamines. 7第7頁，共16頁，2022年，5月20日，10點56

10、分，星期五3.Analysis of selected ionic liquid cations by ion exchange chromatography and reversed-phase high performance liquid chromatography Abstract The chromatographic behavior of ionic liquids - homologues of 1-alkyl-3-methylimidazolium and 4-methyl-N-butyl pyridinium - has been investigated with a

11、strong cation exchange adsorbent. In particular, the dependence of the retention properties of these solutes on mobile phase composition, pH, and buffer concentration was evaluated with the aim of optimizing and improving the selectivity and retention of solute separation. While using the SCX statio

12、nary phase, several interactions occurred with varying strengths, depending on the mobile phase composition. Cation exchange, nonspecific hydrophobic interactions, and adsorption chromatography behavior were observed. Reversed phase chromatography occurred at low concentrations of acetonitrile, elec

13、trostatic and adsorption interactions at higher organic modifier concentrations. Elevated buffer concentrations lowered the retention factors without affecting the selectivity of ionic liquids. Obtained results were further compared to the chromatographic behaviour of ionic liquids in the reversed p

14、hase system. All analyzed ionic liquids follow reversed-phase behavior while being separated. Much lower selectivity in the range of highly hydrophilic compounds is obtained. This suggests preferred use of ion chromatography for separation and analysis of compounds below 4 carbon atoms in the alkyl

15、side chain. 8第8頁，共16頁，2022年，5月20日，10點56分，星期五4.Effect of 1-alkyl-3-methylimidazolium-based ionic liquids as the eluent on the separation of ephedrines by liquid chromatography AbstractThe chromatographic behavior of ephedrines (norephedrine, ephedrine, pseudoephedrine and methylephedrine) on a C18 co

16、lumn was studied with different concentrations of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquids as the eluent at pH 3.0. The addition of ionic liquid has great effects on the separation of these basic compounds: decreasing band tailing, reducing band broadening, and improving resolutio

17、n. The retention times of the analytes increase at first and then decrease with the increase in the concentration of ionic liquid. This effect may be attributed to the competition between imidazolium cations and the polar groups of the analytes for the silanol group on the alkyl silica surface, and

18、also to the formation of weak bilayer electronic structure on the C18 column. Several ionic liquids with different alkyl substituents on the imidazolium cations or with different counterions as the eluents were compared.9第9頁，共16頁，2022年，5月20日，10點56分，星期五5.Ionic liquid-based aqueous two-phase system, a

19、 sample pretreatment procedure prior to high-performance liquid chromatography of opium alkaloids AbstractAn ionic liquid, 1-butyl-3-methylimidazolium chloride (C4mimCl)/salt aqueous two-phase systems (ATPS) was presented as a simple, rapid and effective sample pretreatment technique coupled with hi

20、gh-performance liquid chromatography (HPLC) for analysis of the major opium alkaloids in Pericarpium papaveris. To find optimal conditions, the partition behaviors of codeine and papaverine in ionic liquid/salt aqueous two-phase systems were investigated. Various factors were considered systematical

21、ly, and the results indicated that both the pH value and the salting-out ability of salt had great influence on phase separation. The recoveries of codeine and papaverine were 90.0100.2% and 99.3102.0%, respectively, from aqueous samples of P. papaveris by the proposed method.10第10頁，共16頁，2022年，5月20日

22、，10點56分，星期五6.Suppression of deleterious effects of free silanols in liquid chromatography by imidazolium tetrafluoroborate ionic liquids AbstractSilica-based stationary phases are commonly used in liquid chromatography, but their surface acidity causes known problems, especially when separating basi

23、c compounds. Deleterious effects of free silanols are not fully removed by standard prevention procedures consisting in adding alkylamines or other amino quenchers to the eluents. We found that ionic liquids of the imidazolium tetrafluoroborate class, added to mobile phases at concentrations of 0.51

24、.5% (v/v), blocked silanols and provided excellent thin-layer chromatographic separations of strongly basic drugs which were otherwise not eluted, even with neat acetonitrile as the mobile phase. The silanol suppressing potency of imidazolium tetrafluoroborates was demonstrated to markedly exceed th

25、at of the standard mobile phase additives, like triethylamine, dimethyloctylamine and ammonia. The proposed new mobile phase additives were also demonstrated to provide reliable lipophilicity parameters of base drug analytes as determined by gradient mode of high-performance liquid chromatography. B

26、y applying the readily available and environmentally friendly imidazolium tetrafluoroborate ionic liquids, simple and efficient means of improvement of liquid chromatographic analysis of organic bases were elaborated.11第11頁，共16頁，2022年，5月20日，10點56分，星期五7.Reduction of silano philic interactions in liqu

27、id chromatography with the use of ionic liquids AbstractA suppression of silano philic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or

28、with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC,

29、 RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. A

30、ddition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and consider

31、ed in practical HPLC method development.12第12頁，共16頁，2022年，5月20日，10點56分，星期五8.Determination of Organophosphorous Pesticides in Water Samples Using Ionic Liquid-based Liquid Phase Micro extraction Coupled with High Performance Liquid ChromatographyXie AbstractA novel method for the determination of thr

32、ee organophosphorous pesticides( phorate ,parathion and poxim) in water samples has been developed using ionic liquid-based liquid-phase microextraction coupled with high performance liquid chromatography.The influence of extraction parameters including extraction solvent,the volume ratio of extract

33、ion solvent to sample aqueous,extraction time,extraction temperature and stirring rate was investigated.1-butyl-3-methylimi dazolium hexafluorophosphate was used as extraction solvent and displayed particular advantages compared with volatile organic solvents such as benzene,hexane and acetone.The p

34、roposed method provided enrichment folds of 665,630 and 553 for phorate,parathion and poxim,respectively.The method had good linear range of 0.01-0.1 L/L and the limits of detectionof the three pesticides were in the range of 0.001-0.01 L/L.The RSD of matrix spiked samples were 3.4%,10.5% and 2.4% f

35、or phorate,parathion and poxim,respectively.13第13頁，共16頁，2022年，5月20日，10點56分，星期五9.Ionic liquids as additives in high performance liquid chromatography: Analysis of amines and the interaction mechanism of ionic liquids AbstractAs novel solvents, ionic liquids have many applications in synthesis, cataly

36、sis and analytical separation, i.e. extraction and chromatography separation. In this paper, some amines including benzidine, benzylamine, N-ethylaniline and N,N-dimethylaniline are separated using ionic liquids as additives for the mobile phase in high performance liquid chromatography (HPLC). The

37、effects of the length of alkyl chain or counterions on different ionic liquids and their concentrations on the separation of these analytes are performed. The differences between ionic liquids and tetrabutylammonium bromide (TBA) on the separation of o-, m-, p-phthalic acids are compared and the results show that ionic liquids are ion-pair reagents in essence, although their hydrophobicity and hydrogen bonding also play important roles.14第14頁，共16頁，2022年，5月20日，10點56分，星期五10.Analysis of Phenolic Compounds by Ionic Liquid Based Liquid Liquid Extraction Coupled with High Performance Liquid Chroma