Table 1.

Gradient elution system for 2D-LC-MS/MS analysis

Phase	Pump 2 (HILIC)a, 40 °C, 500 bar			Pump 1 (RP)b, 40 °C, 590 bar
	Time [min]	B [%]	Flow rate [μL/min]	Time [min]	B [%]	Flow rate [μL/min]
1	0.00	100	200	0.00	5	300
2				1.20	5	300
				1.30	0	2000
3				2.15	0	2000
				2.20	0	0
	2.50	100	200
	3.00	90	200	3.00	0	0
	3.80	20	200
				7.45	0	0
4				7.50	5	300
	7.60	20	200
	7.80	100	200
				8.20	50	300
				13.00	70	300
				15.50	85	300
				18.50	100	300
				20.50	100	300
				21.00	5	300
	25.00	100	200	25.00	5	300

^aMobile phase A: water, 0.1% FA, 10 mm ammonium formate; mobile phase B: ACN/water (90:10, v/v), 0.1% FA, 10 mM ammonium formate

^bMobile phase A: water, 0.001% FA, 5 mm ammonium formate; mobile phase B: MeOH, 0.001% FA, 5 mM ammonium formate