Čes. slov. farm. 2009, 58(2):71-77

HPLC study of temperature influence on some enantiomer separations of sulfoxides, determination of some enantiomers of sulfoxides in rat serum

D. Meričko¹, J. Lehotay^1,*, J. Čižmárik²

¹ STU v Bratislave, Fakulta chemickej a potravinárskej technológie, Ústav analytickej chémie

² Univerzita Komenského Bratislava, Farmaceutická fakulta, Katedra farmaceutickej chémie

The methylated-teicoplanin aglycone chiral stationary phase (CSP) was used to study the enantioseparation and temperature behaviour of a set of chiral sulfoxides - nine different aryl methyl sulfoxides, 1-methylsulfinylnaphthalene and 1,1-dimethyl-2-phenylethylsulfinylbenzene in polar organic mode. The effect of temperature on the HPLC separation of aromatic sulfoxides was studied between 10 °C and 50 °C in methanol mobile phases with different concentration of the organic modifier in mobile phase composition. The van't Hoff plots (ln k versus 1/T and ln α versus 1/T, where k is retention factor, T is temperature of chromatographic column, and α is selectivity coefficient) were constructed and thermodynamic data were determined from the slope and the intercept of linear van't Hoff plots for all 12 racemic compounds under the study. The van't Hoff plots were linear for all enantiomers. (S) (+) enantiomeric form was eluted as the first one in any case. Solid phase extraction (SPE) was used for the determination of sulfoxides and clean solutions after SPE was injected into a chiral column. The mobile phase was methanol containing acetic acid (17.48 mmol/l) and diethylamine (4.79 mmol/l). The limits of determination (LOQ) were calculated for all compounds under study. The LOQ values were in the range from 7.0 to 24.2 ng/ml, the recovery of extraction was in the range from 82% to 96%.

Keywords: separation of chiral compounds; methylated teicoplanin CSP; sulfoxidies; solid phase extraction; HPLC

Grants and funding:

Táto práca sa uskutočnila vďaka finančnej podpore Grantovej agentúry Slovenskej republiky (grant 1/0058/08), APVV projekt No. 20-035-205 and VEGA projekt č. 1/4291/07.

Received: March 23, 2009; Accepted: April 15, 2009; Published: February 1, 2009  Show citation