Figure 1.

Comparison of two extraction methods (Method A and B) and two fragmentation methods (CID and HCD) for tear fluid processing. Tear fluid was collected using Schirmer strips (n = 11), and each strip was cut longitudinally into two equal parts. In Method A, proteins were first extracted, and Schirmer strips were removed by filter-aided centrifugation prior to digestion. In Method B, Schirmer strips were cut into 5 mm pieces, and in-strip protein digestion was performed. Digested products from each method then underwent LC–MS/MS analysis using both collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) fragmentation techniques. The average number of unique proteins ($\overline{\mathrm{x}}$) identified per sample using each workflow is displayed.