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

We improved the dry ash procedure for detecting titanium dioxide ( TiO 2 ) in cattle feces containing chromium dioxide ( Cr 2 O 3 ). First, the effect of amount of sodium sulfate ( Na 2 SO 4 ) on the recovery of TiO 2 from cattle feces that contained Cr 2 O 3 was evaluated. Average recovery of TiO 2 at the 2.5 g Na 2 SO 4 level was significantly higher ( P  < 0.0001) than that at 0.75 g Na 2 SO 4 . Second, the effect of Cr 2 O 3 concentration on the recovery of TiO 2 of cattle feces by using two levels of Na 2 SO 4 addition was examined. The recovery of TiO 2 decreased with the increase in the amount of Cr 2 O 3 at the 0.75 g Na 2 SO 4 level but was consistently high at 2.5 g Na 2 SO 4 . Third, the recovery of Cr 2 O 3 from cattle feces was checked. The recoveries of TiO 2 and Cr 2 O 3 were high enough at the 2.5 g Na 2 SO 4 level. Fourth, the improved dry ash procedure (5 mL of concentrated H 2 SO 4 and 2.5 g of Na 2 SO 4 were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO 2 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 TiO 2 analysis in cattle feces containing Cr 2 O 3 .