3-cyclodextrin chromatography column

The reaction mixtures of isophorone were analysed with a gas chromatograph. The GC analyses were carried out with gas chromatograph equipped with a p-cyclodextrine capillary column (analysis temperature dihydroisophorone at 110 °C) and FID. The chromatograms were recorded and peak areas were calculated with Chromatography Station for Windows CSW32 v. 1.2 (DataApex Ltd. 2001, Prague). 

Bordajandi, L.R., Korytar, P., De Boer, J., Gonzalez, M.J. (2005). Enantiomeric separation of chiral polychlorinated biphenyls on P-cyclodextrin capillary columns by means of heart-cut multidimensional gas chromatography and comprehensive two-dimensional gas chromatography applications to food samples. J. Sep. Sci. 28, 163-171. 

The three isomers of cresol are not as readily separated by HPLC, although recent techniques have been developed to accomplish this task. Reversed-phase chromatography columns have been used for the analysis of cresols with limited success. Recently, a new reversed-phase support has been developed that allows complete separation of the three cresol isomers (Bassler and Hartwick 1989). Inclusion complexes of the cresols with p-cyclodextrin cleanly separate the three isomers on commercially available columns (Yoshikawa et al. 1986). Detection limits down to 1 ppm can be obtained by this method. 

Enantiomers have different affinities for the cyclodextrin cavity, so they separate as they travel through the chromatography column. The chromatogram below shows a chiral separation of a by-product found in pesticides. 

Tripathi AM, Mhalas JG, Rama-Rao NV. 1989. Determination of 2,6 and 4,6-Dinitrocresols by high performance liquid chromatography on a beta-cyclodextrin bonded column. J Chromatogr 466 442-445. 

Chiral capillary gas chromatography (GC), performed with a 7-cyclodextrin trifluoroacetyl column, was also used for the determination of ee of isoxazolines <2000JOC8527>. Chiral preparative HPLC has been used to obtain optically pure isoxazolines <1997JME50>. 

The first reports concerning the enantiomeric composition of essential oils were published at the begirming of the nineties. The contents of chiral constituents in different commercial essential oils were investigated on a capillary GC column modified with derivatives of cyclodextrins [17] and on packed columns modified with a native a-cyclodextrin [18]. It was connected with the elaboration of gas chromatography columns modified with cyclodextrins. 

C. S. Wong and A. W. Garrison, Enantiomer separation of polychlorinated biphenyl atropisomers and polychlorinated biphenyl retention behavior on modified cyclodextrin capillary gas chromatography columns, /. Chromatogr. A 866 213 (2000). 

Valko, K., Plass, M., Bevan, C., Reynolds, D. and Abraham, M.H. (1998) Relationships between the chromatographic hydrophobicity indices and solute descriptors obtained by using several reversed-phase, diol, nitrile, cyclodextrin and immobilised artificial membrane bonded high-performance liquid chromatography columns. 

During the hydrogenations samples were taken. These samples were analysed with GC on a P-cyclodextrine capillary column (ethyl lactate on 90 C, dihydroisophorone on 110"C). The analysis provided base-line separation of the enantiomers. The chromatograms were recorded and the peak areas were calculated with a CWS (chromatography work station). Enantimoric excess values were calculated fi om the peak areas of the enantiomers with the usual method [R]-[S]/[R]+[S]. 

Burmester, A. and Jastorff, B. (1996) Enantiosepara-tion in the synthesis of myo-inositol phosphates by high-performance liquid chromatography using a (3-cyclodextrin-bonded column, yourna/ of Chromatography A 749, 25-32. 

J.H. Maguire, Some Structural Requirements for Resolution of Hydantoin Enantiomers with a P-Cyclodextrin Liquid Chromatography Column, J. Chromatogr., 387(1987)453. 

Chiral GC of alcohol 22 [1 mM solutions in methylene chloride, y-cyclodextrin trifluoroacetyl column (30 m X 0.25 mm, head column pressure = 60 psi, oven at 90°C)] is routinely used to determine the % ee of the enzymatic resolution. Typically the molecular weight of the resultant polymer can be determined by gel-permeation chromatography (Asahipak GS-510 column standards pullulans 5.8, 12.2, 23.7, 48.0, 100, 186, 380 kD, Shodex standard P-82) and is usually > 380,000. 

GC using chiral columns coated with derivatized cyclodextrin is the analytical technique most frequently employed for the determination of the enantiomeric ratio of volatile compounds. Food products, as well as flavours and fragrances, are usually very complex matrices, so direct GC analysis of the enantiomeric ratio of certain components is usually difficult. Often, the components of interest are present in trace amounts and problems of peak overlap may occur. The literature reports many examples of the use of multidimensional gas chromatography with a combination of a non-chiral pre-column and a chiral analytical column for this type of analysis. 

Figure 10.1 Analysis of racemic 2,5-dimethyl-4-hydroxy-3[2H]-furanone (1) obtained from a strawbeny tea, flavoured with the synthetic racemate of 1 (natural component), using an MDGC procedure (a) dichloromethane extract of the flavoured strawbeny tea, analysed on a Carbowax 20M pre-column (60 m, 0.32 mm i.d., 0.25 p.m film thickness earner gas H2, 1.95 bar 170 °C isothermal) (b) chirospecific analysis of (1) from the sti awbeny tea exti act, ti ansfened foi stereoanalysis by using a pemiethylated /3-cyclodextrin column (47 m X 0.23 mm i.d. canier gas H2, 1.70 bar 110 °C isothemial). Reprinted from Journal of High Resolution Chromatography, 13, A. Mosandl et al., Stereoisomeric flavor compounds. XLIV enantioselective analysis of some important flavor molecules , pp. 660-662, 1990, with permission from Wiley-VCH.

Figure 10.2 MDGC-MS differentiation between the enantiomers of theaspiranes in an aglycone fraction from puiple passion fruit DB5 pre-column (25 m X 0.25 mm i.d., 0.25 p.m film thickness canier gas He, 0.66 ml/min oven temperature, 60-300 °C at 10 °C/min with a final hold of 25 min) permethylated /3-cyclodextrin column (25 m X 0.25 mm i.d., 0.25 p.m film thickness canier gas He, 1.96 ml/min 80 °C isothermal for 20 min and then programmed to 220 °C at 2 °C/min). Reprinted from Journal of High Resolution Chromatography, 16, G. Full et al., MDGC- MS a powerful tool for enantioselective flavor analysis , pp. 642-644, 1993, with permission from Wiley-VCH.

Rizzi, A. M. and Plank, C., Coupled column chromatography in chiral separations systems employing P-cyclodextrin phases for chiral separation, /. Chromatogr., 557, 199, 1991. 

Organolead and organoselenium compounds were separated satisfactorily by high-performance capillary electrophoresis, using /1-cyclodextrin-modified micellar electroki-netic chromatography with on-column UVV detector set at 210 nm130. 

All aldehydes used in the experiment were freshly distilled or washed with aqueous NaHC03 solution to minimize the amount of free acid. Chiral HPLC was performed using a chiral OJ-H column (0.46 cm x 25 cm, Daicel industries) with a water 717 auto sampler and a UV-vis detector (254 nm). The eluting solvent used was different ratios of hexane and 2-propanol. Chiral gas chromatography analysis was performed in a Shimadzu auto sampler with cyclodextrins columns as chiral stationary phase (fused-silica capillary column, 30 m X 0.25 mm x 0.25 gm thickness, /3-Dex-120 and /3-Dex-325 from Supelco, USA) using He as a carrier gas (detector temperature 230 °C and injection temperature 220 °C). 

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