Fig. 1. Plots showing optimization tests for determining the volume of concentrated sulfuric acid and concentration of the TiCl3 reagent to be used for a 10 mL sample injection. In panel a), sulfuric acid volume varied while keeping the Ti(III) reagent at 2 mL of 5% (w/v) TiCl 3. In panel b), the volume of sulfuric acid was set to 7 mL while varying theconcentration of TiCl3 used.