Application of 193 nm ultraviolet photodissociation (UVPD) for phosphoproteomics analysis of IMAC enriched HeLa and HCC70 lysates. HCC70 cells were either maintained in full media or serum starved for 6 hours prior to lysis. Each sample was analyzed by three UVPD and three HCD technical replicates using an Orbitrap Fusion mass spectrometer equipped with a Coherent 193 nm excimer laser. Using UVPD, a/x, b/y, and c/z ions were generated and improved phosphate retention was observed on product ions.