Technical Note: A procedure for the preparation and quantitative analysis of samples for titanium dioxide1

Abstract

A procedure was developed for the rapid analysis of titanium dioxide (TiO₂) concentrations in feed and fecal samples. Samples were digested in concentrated H₂SO₄ for 2 h, followed by addition of 30% H₂O₂, and absorbance was measured at 410 nm. Standards were prepared by spiking blanks with increasing amounts of TiO₂, resulting in a linear standard curve. Complete analysis using this procedure can typically be accomplished within 4.5 h. This procedure was compared to a previously published dry-ash procedure for the analysis of TiO₂ in bovine fecal samples. Three sources of OM devoid of TiO₂ (a forage sample, a bovine fecal sample without Cr₂O₃, and a bovine fecal sample containing Cr₂O₃) were spiked with graded amounts (0, 2, 4, 6, 8, or 10 mg) of TiO₂. With our procedure, TiO₂ recoveries averaged 96.7, 97.5, and 98.5%, for the three OM sources, respectively, vs. 74.3, 83.8, and 53.1% for the same samples analyzed using the dry-ash method. These results suggest that our procedure is a rapid and accurate alternative to dry-ash procedures for the determination of TiO₂.