For the analysis of the 104 macrocyclic peptides used in purification studies, a 1290 Infinity II UHPLC with 6230 time-of-flight LC/MS mass detector was used to obtain the retention times of desired compounds. An 8 min standard method gradient 5% to 95% acetonitrile/water with 0.1% trifluoroacetic acid at 0.6 mL/min in 7 mins followed by a 1 min equilibration was used in this work. An ACQUITY UPLC Peptide CSH C18 (Waters, Milford, MA, USA) analytical column (130Å, 1.7 µm, 2.1 mm X 100 mm) was used at 65 ºC. The mobile phases are LC-MS grade water and acetonitrile from Fisher Scientific, containing 0.1% trifluoroacetic acid as a pH modifier.