Supercritical fluid chromatography chiral columns

The submitters determined the crystalline hydroxy esters to be >99.9% diastereomerically pure by supercritical fluid chromatography (EMdiol silica column and a Chiralcel (+) OD-(H) column (Chiral... 

ViUeneuve, M.S., Anderegg, R.J. Analytical supercritical fluid chromatography using fully automated column and modifier selection valves for the rapid development of chiral separations. J. Chromatogr. A 1998, 826, 217-225. 

Enantioselective separation by supercritical fluid chromatography (SFC) has been a field of great progress since the first demonstration of a chiral separation by SFC in the 1980s. The unique properties of supercritical fluids make packed column SFC the most favorable choice for fast enantiomeric separation among all of the separation techniques. In this chapter, the effect of chiral stationary phases, modifiers, and additives on enantioseparation are discussed in terms of speed and resolution in SFC. Fundamental considerations and thermodynamic aspects are also presented. 

In addition to high-performance liquid chromatography (HPLC), the chiral resolution using CMPAs was also carried out by supercritical fluid chromatography (SFC) [91] and capillary electrochromatography (CEC) [92-98]. Salvador et al. [91] used dimethylated /1-cyclodextrin as the mobile phase additive on porous graphite carbon as the solid phase for the chiral resolution of tofizopam, warfarin, a benzoxazine derivative, lorazepam, flurbiprofen, temazepam, chlorthalidone, and methyl phehydantoin by SFC. The authors also studied the effect of the concentration of dimethylated /1-cyclodextrin, the concentration of the mobile phase, the nature of polar modifiers, outlet pressure, and the column temperature on the chiral resolution. 

P. Biermanns, C. Miller, V. Lyon, and W. Wilson, Chiral resolution of /3-blockers by packed-column supercritical fluid chromatography, LC-GC Mag., 7/(10) 744 (1993). 

Biermanns et al. reported the chiral resolution of /3-blockers, including propranolol, metoprolol, and atenolol using packed-column supercritical fluid chromatography [38]. A Chiracel OD column with a mobile phase of 30% methanol with 0.5% isopropylamine in carbon dioxide was used for the separation. A baseline separation of isomers was obtained in less than 5 min at a mobile-phase flow rate of 2 ml/min. While keeping the column outlet pressure constant, the flow rate was increased to 4 ml/min and it was noted that, although the retention was reduced, the resolution remained the same. Both R- and S-propranolol gave linear responses from 0.25-2500 ppm with a correlation coefficient of >0.9999. The detection limit was approximately 250 ppb for a S/N ratio of 3. The reproducibility for both R- and S-propranolol was less than 1.5%. It was also noted that 0.09% R-propranolol can be quantitated in the presence of 2500 ppm of S-Propranolol. 

A polar stationary phases such as ODS and TMS and polar such as CN, diol, or NO2 have been successfully applied to the separation of monosaccharides Separation of maltodextrin derivatized with trifluoroacetic anhydride using FID and a CN packed column Capillary supercritical fluid chromatography-MS is well suited to confirm the identity of the TMS derivative of inositol triphosphate Chiral analytes Enantioseparation... 

Biermanns, E., Miller, C., Lyons, V., and Wilson, W.H. 1993. Chiral resolution of 3-blockers by packed column supercritical fluid chromatography. Liquid Chromatography Gas Chromatography, 10 744—7. 

R. M. Smith, Chiral chromatography using sub- and supercritical fluids, in C. L. Berger and K. Anton (eds.), Supercritical fluid chromatography with packed columns. Techniques and Applications, Marcel Dekker, New York, 1998, Chapter, 8, pp. 223-249. 

In addition to normal- and reversed-phase chromatography, silver ion HPLC, RP ion-pair HPLC, chiral separation, and supercritical fluid chromatography have been used for analysis of lipids [3]. In silver-ion HPLC, the counterion of an ion-exchange column such as sulfonate is exchanged with silver ions. Only the degree of unsaturation in the lipid molecule determines retention. In RP ion-pair HPLC, different ion-pairing agents, such... 

Villeneuve, M.S. Anderegg, R.J. Analytical Supercritical Fluid Chromatography Using Fully Automated Column and Modifier Selection Valves for the Rapid Development of Chiral Separations, 7. Chromatogr. A 826, 217-225 (1998). 

Wolf C, Pirkle WH. Enantiomer separation by sub- and supercritical fluid chromatography on rationally designed chiral stationary phases. In Anton K, Berger C, eds. Supercritical Fluid Chromatography with Packed Columns. Chromatographic Science Series. Vol 75. New York Marcel Dekker, 1998, Chap 9. 

Gyllenhaal, O. Packed column supercritical fluid chromatography of a peroxysome proliferator-activating receptor agonist drug Achiral and chiral purity of substance, formulation assay and its enantiomeric purity. J. Chromatogr. 2004 , 1042,173-180. 

GC) (HPLC] 1 FC) (Capillary) gas, (high-performance) liquid, or supercritical fluid chromatography. Where used for ee determination, either chiral columns or diastereomeric derivatization is implied. 

Scheme 5.1 A protocol for sample preparation prior to chiral analysis of the pollutants. Note that this is only a brief outline of the sample preparation procedure. MAE, microwave assisted extraction SE, Soxhlet extraction ASE, accelerated solvent extraction SFE, solid phase extraction CC, column chromatography HPLC, high performance liquid chromatography SFC, supercritical fluid chromatography GPC, gel permeation chromatography.

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