Ionic substances with melting points at or close to room temperature are referred to as ionic liquids. Interest in ionic liquids for their potential in different chemical processes is increasing, because they are environmentally benign and are good solvents for a wide range of both organic and inorganic materials. In this study, a capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts is reported. The method, in which 1-alkyl-3-methylimidazolium-based ionic liquids are used as the running electrolytes, is simple and reproducible. The separation mechanism seems to involve association between the imidazolium cations and the polyphenols. The role of the alkyl substituents on the imidazolium cations was investigated and will be discussed.

Mixtures of randomly substituted sulfated cyclodextrins (degree of substitution, approximately 7-10) were successfully used as chiral additives for the enantioseparation of 56 compounds of pharmaceutical interest, including anesthetics, antiarrhythmics, antidepressants, anticonvulsants, antihistamines, antihypertensives, antimalarials, relaxants, and bronchodilators. The separations were accomplished at pH 3.8, with the anode at the detector end of the column. Under these conditions, in which electroosmotic flow is directed toward the injection end of the column and the electrophoretic mobility of the negatively charged cyclodextrin is toward the detector, none of the analytes reached the detector in the absence of the sulfated cyclodextrin. Most (40) of the successfully resolved enantiomers contained basic functionality and a stereogenic carbon. However, the versatility of this sulfated cyclodextrin additive was also demonstrated by the fact that three atropisomers, 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate, 1.1'-binaphthyl-2,2'-diol, and Troger's base, and several neutral analytes were also successfully enantioresolved under these conditions. The separation mechanism seems to involve inclusion complexation.

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This review focuses on the emerging role of sulfated cyclodextrins in the capillary electrophoretic (CE) separation of chiral analytes. Since being introduced as enantioselective agents for CE in 1995, these anionic additives have continued to demonstrate remarkable application universality. The broad spectrum of chiral compounds successfully separated using this approach includes acidic, basic, neutral, and zwitterionic species. This impressive array of analyte structures is derived from a growing diversity of compound classes including pharmaceuticals, plant extracts, biomarkers, herbicides, alkaloids, fungicides, and metal ions. Moreover, literature reports highlight the minimal optimization required to achieve a successful separation. Based on these findings, sulfated cyclodextrins appear to be well suited for the development of a more universal, comprehensive separation strategy for chiral compounds. This review explores this proposition by beginning with the structure and migration properties of sulfated cyclodextrins, using applications to highlight the separating power of this technique and ending with a pragmatic, comprehensive separation strategy.

Various Brassica species accumulate Se into the thousands of ppm. This suggests some of them as candidates for Se phytoremediation. Brassica juncea (Indian mustard) was used to accumulate selenium by growing with sodium selenite as the selenium source under hydroponic conditions resulting in Se accumulation of up to hundreds of ppm in various parts of the plant. To date, few selenium speciation studies have been done in plants, with most studies reporting total selenium concentration in various parts of the plant. Se species extraction was evaluated by several digestion/extraction procedures, including the use of HCl, Tris-HCl buffer, and enzymatic hydrolysis (using proteinase K and protease XIV). The best extraction was obtained with proteinase K (extracting approximately 75% of the total Se present in the plant). Some of the species produced by the plant, such as selenomethionine, can be identified at ppb levels by RP-HPLC-ICPMS, since standards are readily available. Others needed to be further characterized by ES-MS. Enzymatic hydrolysis releases mostly Se-methionine from juncea leaves, although other Se-containing species can also be observed by HPLC-ICPMS. In this initial study, the possible identification (by ES-MS) of a small chromatographic peak containing a Se-S bridged seleno amino acid with a structure similar to cystine is suggested.

Several different derivatized /8-cyclodextrlns were synthesized and used as chiral stationary phases In normal-phase liquid chromatography. The multiply substituted derivatives were made with acetic anhydride, (/?)-and (S )-1-( 1-naphthyl)ethyl Isocyanate, 2,6-dlmethylphenyl Isocyanate, and p-toluoyl chloride. The first successful cyclodextrln-based, normalphase separation of enantiomers was accomplished on these derivative phases. In contrast to chiral separations on the native /9-cyclodextrln stationary phase, the enantiomeric separation mechanism on these new phases Is not thought to be dependent on Inclusion complexation. The similarities and differences between the derivatized cyclodextrin stationary phases and the cellulosic stationary phases are discussed.

Sulfated beta-cyclodextrin, a negatively charged chiral selector, was used for the enantiomeric separation of racemic terbutaline by capillary electrophoresis. Chiral separation was found to increase with decreasing cyclodextrin concentration. Host-guest complex binding constants for this system were determined by UV difference spectroscopy (Kav = 1490 M-1) and by CE under conditions of minimal EOF and reversed polarity (K1 = 1730 M-1, K2 = 1590 M-1, alpha = 1.09). The effect of organic modifiers, methanol, and acetonitrile was also studied over a wide range of modifier concentrations. Binding constants decreased while selectivity increased with increasing organic modifier concentration (10% MeOH: K1 = 1590 M-1, K2 = 1130 M-1, alpha = 1.41. 10% ACN: K1 = 1320 M-1, K2 = 870 M-1, alpha = 1.52). Experimental results are discussed in the context of existing separation models.

A capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts was developed using a quaternary ammonium salt as the main electrolyte solution. Seven polyphenols were separated and identified. The separation mechanism seems to involve association between quaternary ammonium cations and the polyphenols. Migration times roughly correlate with the size of the known phenols. The role of the alkyl substituents on the quaternary ammonium ions was investigated and is discussed. The method of analysis proposed herein exhibits high reproducibility in terms of migration times for a complex mixture using a single component background electrolyte.