These test methods are intended as a quick and reliable procedure for measuring the titanium dioxide pigment content of aqueous slurries. Included with the pigment content in the percent solids are the various nonvolatile additives used in preparing a stable slurry. Because the aluminum and silica oxide treatments on the more highly treated titanium dioxide pigments may change somewhat with prolonged drying, in the oven method the solids of the slurry are considered dry after heating at 105°C for 60 to 65 min. The high temperature associated with the infrared moisture analyzer may also effect a change in the aluminum and silica oxide treatment on highly treated TiO₂ products. Therefore, care in selection of time and temperature are critical to obtain accurate results with the infrared method. With the short duration of test associated with the microwave drying system, overdrying is not a concern.