Figure 1: FPOP optical bench for adalimumab biosimilar analysis.

Sample is mixed with H₂O₂, adenine radical dosimeter and glutamine scavenger and loaded into the syringe. Sample is pushed through the fused silica capillary through the focused beam path of a KrF excimer UV laser. The UV light photolyzes H₂O₂ into hydroxyl radicals, which oxidizes the protein and adenine dosimeter. The syringe flow pushes the illuminated sample out of the path of the laser prior to the next laser pulse, with an unilluminated exclusion volume between illuminated regions. Immediately after oxidation, the sample is passed through an inline UV spectrophotometer, which measures the UV absorbance of adenine at 265 nm. Sample is then deposited into a quench buffer to eliminate the remaining H₂O₂ and secondary oxidants.