An improved dry ash procedure for the detection of titanium dioxide in cattle feces

We improved the dry ash procedure for detecting titanium dioxide (TiO₂) in cattle feces containing chromium dioxide (Cr₂O₃). First, the effect of amount of sodium sulfate (Na₂SO₄) on the recovery of TiO₂ from cattle feces that contained Cr₂O₃ was evaluated. Average recovery of TiO₂ at the 2.5g Na₂SO₄ level was significantly higher (P<0.0001) than that at 0.75g Na₂SO₄. Second, the effect of Cr₂O₃ concentration on the recovery of TiO₂ of cattle feces by using two levels of Na₂SO₄ addition was examined. The recovery of TiO₂ decreased with the increase in the amount of Cr₂O₃ at the 0.75g Na₂SO₄ level but was consistently high at 2.5g Na₂SO₄. Third, the recovery of Cr₂O₃ from cattle feces was checked. The recoveries of TiO₂ and Cr₂O₃ were high enough at the 2.5g Na₂SO₄ level. Fourth, the improved dry ash procedure (5mL of concentrated H₂SO₄ and 2.5g of Na₂SO₄ were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO₂ by the improved dry ash procedure was significantly higher (P=0.0077) than that by the wet ash procedure. Thus, the improved dry ash procedure can be used for TiO₂ analysis in cattle feces containing Cr₂O₃.