We describe an aerosol-liquid cycle that launches the autocatalytic amplification of any initial imbalance of the order of ${10}^{-7}\%$ (1 ppb) up to total chiral purity in a single step process. Crystal nucleation of ${\mathrm{NaClO}}_3$ is initiated at the aerosol air-water interface where, due to the accumulation of ambient chiral impurities or added hydrophobic chiral aminoacids in tiny concentrations (ppb), the initial levorotatory ($l$) and dextrorotatory ($d$) excess will not be produced with equal probability. The enantiomeric yield is then enhanced up to homochirality by recycling the crystallites through a liquid phase. In the absence of added catalysts this process leads to preferential ($d$) homochiral crystallizations in a ratio of $4:1$ which is due to ambient contamination. By adding only 2 ppb of ($L$) or ($D$) Phe, we induce a final preferential homochiral crystallization of ($d$) or ($l$) handedness, respectively, in a ratio of $2:1$.

• Received 10 June 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.146102