A sample cell for an analysis instrument, having an outer body forming a sample reservoir therein; a directional fill valve disposed in an upper end of the outer body and forming an upper end of the sample reservoir, the fill valve for accepting a sample during filling, and preventing sample leakage while providing venting after filling; and a film covering a lower end of the outer body, and forming a bottom end of the sample reservoir, the film for presenting the sample to an analysis focal spot of the analysis instrument. The disclosed sample cell is especially suited for an x-ray analysis engine having a focal spot requiring alignment with the sample in the sample cell. At least one x-ray optic may be disposed in an excitation and/or detection path, requiring alignment to the focal spot, in e.g., a WDXRF or EDXRF system.