The primary driver of the peCOD method chemistry is advanced oxidation induced by photocatalysis with Titanium Dioxide (TiO2). Pure TiO2 is only photo-active at wavelengths below 380 nm. This is because a certain amount of light energy is required to bump the electrons around and cause the behaviors that we associate with photocatalysis. The UV LED in the PeCOD COD Analyzer operates at a peak wavelength of 365 nm, with a minimum 360 nm and maximum 370 nm, ensuring that efficient photocatalysis is achieved.