A materials analysis device (2) comprises an inner receptacle (4), incorporating a filter (5) at its lower end, within an outer receptacle (6). Gas inlet/outlet ports (8, 10) are arranged to provide a means whereby solvent can be caused to pass between the receptacles (4, 6) via filter (5). Solvent in the receptacles (4, 6) is arranged to be heated and its temperature assessed. In use in one embodiment, a solute material to be analyzed is introduced into outer receptacle (6) and a solvent is introduced into inner receptacle (4). The solvent is caused to pass back and (15) forth between the receptacles (4, 6) via the filter (5) until a saturated solution of the solute is present in inner receptacle (4). This may be removed for analysis. By undertaking the process described at a range of temperatures, a solubility profile for the solute can be determined.