The aim is to determine the amount of absorbtion of the one component of a mixture at the nemtic/air interface using neutron reflection. The host material in the mixture will be a cyanobiphenyl nematic, 5CB. The solutes will be deuterated versions of the minor components(5CT and 8OCB) in a commercial liquid crystal mixture and a fluorinated liquid crystal-like dopant, F17. They are thermodynamically closer to the smectic A phase and so are expected to have a preference for the surface, where layering can occur more easily. The temperature dependence, concentration dependence and the influence of the solute type will be explored. Preliminary experiments on CRISP have not been sensitive enough to determine the adsoorbtion of 5CT but they have shown promising, possibly bulk phase sensitive behaviour for F17.