Quantitative Adsorption and Solution Phase Photocatalytic Reactions with HPLC

High performance liquid chromatography (HPLC) is used to quantitatively analyze solution phase molecules to get information on: (i) the uptake of environmentally relevant ligands onto nanoparticle surfaces; (ii) the concentration reactive oxygen species (ROS) generation by nanoparticles and; (iii) photocatalytic product formation/reactant degradation. A Dionex Ultimate 3000 HPLC system equipped with an autosampler and a diode array detector is utilized to achieve these objectives. In a typical adsorption experiment, the initial concentration of the interested ligand is quantified with the HPLC followed by the addition of the nanoparticles, mix overnight, and separate the supernatant by filtration and ultracentrifugation to quantify the final concentration of the ligand by HPLC. For ROS quantification a probe molecule is added to the reaction mixture and the products formed are separated and quantified. This method of analysis has proved to give rapid, reproducible results as shown by the consistency of the calibration standards.