Effect of solutes on the heterogeneous nucleation temperature of supercooled water: an experimental determination.

We investigate the effect of solute concentration on the heterogeneous ice nucleation temperature (T(het)) of aqueous solutions of both NaCl and d-glucose. An automatic lag time apparatus (ALTA) technique allows the dependence of T(het) on solute concentration to be determined with statistical significance. Our results point to the solute-induced lowering of T(het) being a factor of two times the equivalent melting point depression at any fixed concentration, the same factor reported for homogeneous nucleation experiments with small molecular weight solutes.