Comparison of two methods for the gas chromatographic determination of thermodynamic parameters of enantioselectivity

摘要: Abstract The thermodynamic parameters responsible for the formation of diastereomeric associates between enantiomers methyl lactate and two Lipodex E columns [with 5.37% or 10.08% octakis(3- O -butanoyl-2,6-di- -pentyl)-γ-cyclodextrin in SE 54] were calculated using different methods. Method A was based on direct determination Δ(Δ G R , S 0 ) from experimental values chiral separation factor α obtained at temperatures columns. B relies relative retention respect to an inert reference standard a column containing only solvent that same reactor cyclodextrin derivative S. 54 used as n -heptane, -octane -nonane standards. Obtained results Δ R,S (Δ show data by are too small dependent concentration selector diluted stationary phase. Since dependence ln 1/ T nonlinear, it not possible calculate H this method. Results essentially independent choice compound mixed