Table 1.

Program of time controlled steps for the LC gradient pump and the six-port switching valve.

Time (min)	Flow (mL/min)	Solvent A (%)	Solvent B (%)	Valve Position
0	0.25	70	30	A
5	0.25	70	30	B
11	0.25	40	60
12	0.25	0	100
17	0.25	0	100
19	0.25	70	30	A
21	0.25	70	30

Solvent A: Ammonium Acetate buffer 2 mM (pH 4.6)/Acetonitrile (99.5/0.5 v/v)

Solvent B: Ammonium Acetate buffer 2 mM/Acetonitrile/glacial acetic acid (2/97/1; v/v)