Table 1. LC gradient for detection of barbiturates in raw milk (A = water; B = acetonitrile)

Time (min)	Flow rate (μL/min)	A%	B%
0.0	0.3	90.0	10.0
0.5	0.3	90.0	10.0
0.6	0.3	73.5	26.5
4.0	0.3	73.5	26.5
4.1	0.3	75.0	25.0
5.5	0.3	73.5	26.5
6.0	0.3	73.5	26.5
9.0	0.3	20.0	80.0
9.1	0.3	90.0	10.0
10.0	0.3	90.0	10.0