Gas chromatographic enantiomer separation of agrochemicals using modified cyclodextrins

Abstract

SummaryThe enantiomers of phenoxypropionic acid type herbicides have been resolved by capillary gas chromatography employing modified cyclodextrins as chiral stationary phases. Excellent separations were obtained with columns containing a 1 :I mixture of per-0-pentylated and per-0-methylated 6-cyclodextrin.pesticides and herbicides may differ by orders of magnitude, but little is known about their selective action. It has been found that the activity of the D( +) forms of some chiralphenoxypropionic acid derivatives (1-3; Figure 1) which are used as herbicides is about twice as high as that of the racemates.The enantiomers of the methyl esters of mecoprop and dichlorprop were also resolved on octakis(3-O-butyryl-2,6-di-O-penty1)y-cyclodextrin. On this phase the order of elution of the enantiomers was temperature-dependent, the elution order being reversed as the temperature passed through the isoenantioselective temperature. This is the first time such behavior has been observed with cyclodextrin derivatives.The enantiomers of the polychlorinated polycyclic pesticides cis-and trans-chlordane, oxychlordane, heptachlor, heptachlorepoxide, and three chiral organophosphorus pesticides could be resolved using selectively derivatiied cyclodextrin derivatives.

Chiral Analysis of Monoterpenes in Volatile Oils From Propolis

“…17,18 In essential oils, this analysis possesses a great importance in the control of quality of these oils, where they supply important information about its authenticity detecting the presence of possible synthetic adulterants. 19 So far, no reports are available about the enantiomeric composition of volatile oils from propolis.…”

Synthesis and Chromatographic Evaluation of the new phase heptakis (3-O-pentafluoropropionyl-2,6-di-O-pentyl)-β-cyclodextrin

“…The capillary is then filled with a 0.2% solution of the cyclodextrine derivative and OV 1701 (1:1; m m -1 ) according to the procedure described previously. 2 …”

“…[1][2][3][4][5][6][7][8][9][10][11] Various chiral mono and sesquiterpenes common to essential oils and other economically important products could be resolved on columns coated with per-O-alkylated/acylated cyclodextrins. [11][12][13][14][15][16] The number of cyclodextrin derivatives that is prepared and evaluated for enantioselective gas chromatography is still declining in recent years.…”

Enantiomer Separation of Mandelates and Their Analogs on Cyclodextrin Derivative Chiral Stationary Phases by Capillary Gc

“…1,2 On CD CSPs, the enantiomers of a wide variety of structurally diverse racemates have been resolved. A number of chiral recognition mechanisms have been established depending on the particular chiral guest and cyclodextrin derivative under investigation.…”

“…A number of chiral recognition mechanisms have been established depending on the particular chiral guest and cyclodextrin derivative under investigation. [1][2][3][4] However, a reasonable model is still lacking to explain GC enantiomer separation on cyclodextrin based CSPs.…”