Do you have a reference that says what molecule is created, that has a chromaphore in the visible, from TiCl2 and H2O2? Should you even be mixing a powerful reducing agent (Wikipedia says TiCl2 will relese hydrogen from water) with a strong oxidizing agent? How will you get the color from the TCA? What is TCA dissolved in? Because it is decomposed by water, and you do have some with your H2O2, correct?