Gamma-radiolysis of chiral molecules: R(+)-limonene, S(-)-limonene and R(-)-a-phellandrene

Three isomeric chiral terpenes, R(+)-limonene, S(-)-limonene and R(-)-a-phellandrene were γ-radiolyzed in sealed vials at room temperature with a total radiation dose of 317 kGy. The radiolyzed samples were analyzed by FT-IR, electronic absorption spectroscopy, liquid chromatography using a diode-array detector (HPLC-DAD) and by polarimetry. Despite a relatively high radiation dose used, all the chiral molecules selected have shown a low radioracemization rate. This fact and the role played by the impurities in the selective radio-degradation of one of the two enantiomers has been discussed in the context of the origin of chirality in prebiotic molecules and the chirality enhancement in a prebiotic world. The results were also discussed in the frame of the radiosterilization technique of chiral drugs, perfumes and food components. This revised version was published online in July 2006 with corrections to the Cover Date.