Article Title: Biomarker-based Asthma Phenotypes of Corticosteroid Response Article Snippet: ..Amino acids in urine were separated over a Prodigy C18 column (150 × 2.0 mm, 5 mm, Phenomenex, Torrance, CA, USA), at a flow rate of 0.2 ml/min using a discontinuous gradient generated with mobile phases comprised of 0.2% formic acid in water (solvent A) and 0.2% formic acid in acetonitrile (solvent