Pgc guard columns

Capillary tubing (o.d.=360um, i.d.=75um) was trimmed to a length >30cm with a small portion of the polyimide coating removed. A Sutter P-2000 micropipette laser puller was used to stretch the glass capillary into the final emitter geometry. The closed, tapered tip was then opened via emersion in 48% hydrofluoric acid for 2.5 minutes. 3um PGC packing material was harvested from PGC guard columns (Thermo Fisher Scientific, 35003–014001) and resuspended in optima grade methanol in a 1.5mL glass vial. A micro flea stir bar was added to provide agitation, and the slurry and etched capillary were placed in a pressure injection cell (Next Advance, PC77-MAG). The capillary was packed with PGC material using ~1000psi industrial grade nitrogen until 30cm of the capillary was full. Pressure was released and the same packing conditions were used to flush the column with methanol and air, sequentially. Columns were stored at room temperature until use.

Water (H₂O, 223623) acetonitrile (ACN, A955), methanol (MeOH, A456), chloroform (C298), formic acid (FA, A117), tris base (BP152), urea (U15), and hydrochloric acid (HCl, A144SI) were purchased from Thermo Scientific. Acetone (179124), sodium dodecyl sulfate (SDS, 7173C), dithiothreitol (DTT, D9779), and iodoacetamide (IAA, I6125) were purchased from Millipore Sigma. Trypisn (V5113) was purchased from Promega (Madison, WI). RPLC packing materials (4451IP, 4472IP) were purchased from Osaka Soda Co (Osaka, Japan). PGC packing material was harvested from ThermoFisher PGC guard columns (35003-014001). Capillary tubing (1068150019) was purchased from PolyMicro. All other sources are listed.