The thirty-eight fractions that inhibited S. aureus biofilms were resuspended in 50% MeOH/H2O at a concentration of 1 mg/mL and analyzed by LR-LCMS for the presence of pseudochelin A. The LC was equipped with a Phenomenex Kinetex 5μm C8 (100 x 3.0 mm) column and run under the following method, flow rate of 0.3 mL/min, hold 10% ACN/H2O + 0.1% formic acid (FA) for 3 min then gradient to 100% ACN + 0.1% formic acid over 14 min. Pseudochelin A eluted between 8 to 9 min and was present in 25 fractions (Table ).