Selecting a stationary phase for a fluid analyzer using certain criteria to determine an appropriate material for use in, for instance, a micro fluid analyzer. High absorption of an analyte or sample, low water sorbency and high porosity or permeability of the material may be sought. A selected material may incorporate a toughening agent using a neutral leaving group. A selected material may have a capping agent to promote hydrophobicity. A selected material may be a hydrophobic polymer. The selection of a stationary phase may involve molecular modeling.