Abstract: The amount by weight of TiO2 per gallon of paint in a paint sample is determined by X-ray fluorescence spectroscopy. The sample is prepared by weighing a portion of the sample while wet and then drying the sample. The dried sample is then calcined to produce an ash residue, which is weighed. The ash residue is then ground and heated to drive off any remaining moisture before being fused with a flux material into a glass bead. The amount of TiO2 in the fused glass bead is determined by an X-ray fluorescence instrument which has been previously calibrated with similar fused glass beads having known amounts of TiO2. The quantitative result of the X-ray fluorescence determination is then extrapolated back to determine the pounds of TiO2 per gallon of paint.