. Author manuscript; available in PMC: 2015 Feb 20.

Published in final edited form as: Prostate. 2014 May;74(7):722–731. doi: 10.1002/pros.22792

TABLE I.

Timetable for LC/MS/MS Gradient Elution Profiles and Switching Valves

Time (min)	Shimadzu gradient for analytical column elution			Waters gradient for guard column cleanup			Switching valves
Time (min)	Flow rate (μl/min)	Mobile phase A (%)	Mobile phase B (%)	Flow rate (μl/min)	Mobile phase A (%)	Mobile phase B (%)	ID	Position	Flow direction
0.00	175	87	13	200	87	13	1	A	To cleanup column
0.00							2	B	To waste
1.00							1	B	To analytical column
4.50							2	A	To mass spec source
4.75				200	87	13
5.00				350	0	100
8.25	175	20	80
8.50	175	5	95	350	0	100
8.75				350	87	13
9.50	175	5	95				2	B	To waste
10.0	175	87	13
14.0							1	A	To cleanup column
15.0	175	87	13	350	87	13