Analytes in the extracts were separated on a reversed phase C18 column (250mm×2.1 mm, 5m)
using a mobile phase of a 3:7 (v/v) mixture of 0.1% formic acid in acetonitrile and an ammonium formate buffer (ammonium
formate:formic acid:acetonitrile:water, 1:5:50:950, v/v/v/v) running at a flow rate of 0.2 ml min−1.