We investigate a force that has been predicted to discriminate molecules by their chirality when they are in the presence of an optical field with a polarization-helicity gradient. We investigate several experimental geometries for observing evidence of this force via enantiometer separation in racemic mixtures. We do this with singular-optical beams carrying a polarization helicity gradient across their transverse mode. Molecular diffusion and the dipole force - an intensity-gradient force - have so far precluded measurements of this force.