The assay was performed as previously described by Zerfas et al. were dissolved in MeCN/DMSO 9:1 to achieve a final concentration of 0.5 mg/mL. The mobile phase A was 50 mM NH4Ac adjusted to pH 7.4 with ammonia, while mobile phase B was iPrOH. The flow rate was set to 1.0 mL/min, the UV detector was set to 254 nm, and the column temperature was kept at 30 °C.