Analysis Of The Enantiomers Ratio Of Citronellal From Indonesian Citronella Oil Using Enantioselective Gas Chromatography

Citronellal 97,3% has been isolated from Java citronella oil (Cymbopogon winterianus) from Yogyakarta Indonesia by fractional distillation under reduced pressure (5 cmHg, 110-120 oC). Citronellal has two optical isomerics that can be separated by capillary column of chiral GC phase. Enantioselective capillary GC with heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin (β-DEX-225) as stationary phase has been used for analysis of the enantiomers ratio of citronellal. The analysis of enantiomer ratio showed that citronellal contain of 88.21% ee of (R)-(+)-citronellal. Physical properties of isolated citronellal showed that the compound was (+) enantiomer. Structure identification of citronellal was carried out by GC-MS, IR, and 1H NMR, resulted identical fragment and spectra with standard citronellal. Theoretical study with semiempirical-AM1 method showed that energy of (R)-(+)-citronellal on the β-DEX 225 was lower than its (S)-(-)-citronellal.