In the AOAC procedure [4], a sample mass of 1.5 g was accurately
weighed out and transferred to a 400 mLdigestion tube, followed
by addition of 5 mL H2SO4 and 2 mL H2O.Themixturewas
heated at 250 °C for 3 h. The resulting extract was transferred
to a 100 mL volumetric flask, 1 mL of Ti stock standard solution
was added, and the volume was completed with water.