© 2012 AOAC INTERNATIONAL
particles, centrifuge samples and transfer liquid layer to funnels
lined with filter paper.
(
3
)
Sample concentration.—
For each sample that will be cleaned
0.00
90
10
0
14.5
90
10
0
14.6
4
0-60
a
1
60-40
a5
9
0
2
76
.0
4
0-60
a
1
--5960-40
a
0
2
67
.1
0
10
90
2
89.9
0
0
10
90
a
Appropriate gradient conditions must be
established with each column to adequately
resolve vitamin B12 and riboflavin and to elute
vitamin B12 between approximately 24 and 27
minutes. To establish appropriate gradient
conditions with a new column, set the gradient
composition at 14.6 and 27.0 minutes to the
midpoint of the allowable range from the table
above. Inject the resolution test solution and
calculate the resolution (R) between the vitamin
B12 and riboflavin peaks (See K. Resolution
Calculation). Adjust the mobile phase
composition at 14.6 and 27.0 minutes until R is >
1.5.
