This shows one advantage of using an alkaline eluent for the analysis of procainamide in serum such as procainamide. Procainamide cannot be separated from other serum components at pH 3 or 7. However, since procainamide, which is one of a tertiary amine, dissociates a little at pH11, in consequence, it is strongly retained by the packing material of Asahipak ODP-50 4D ( a column for reversed phase chromatography ) and can be separated from other serum components.
As explained above, for the analysis of basic drugs which have tertiary amino groups, an alkaline eluent at pH11 is effective.
1) Dissolve procainamide in CH3CN (1.0mg/mL).
2) Put 10 µL of the above in the centrifuge tube and blow dry it.
3) Add 1,000 µL of the serum and stir.
4) Add 3,000 µL of CH3CN and stir.
5) Centrifuge (3,500rpm , 20min) skim and filtrate by using a 0.45 micron filter to make a sample.
6) Inject 20 µL of the sample.
Sample : Procainamide in serum
Column : Shodex Asahipak ODP-50 4D (4.6mmID*150mm)
Eluent : 25mM Phosphate buffer/CH3CN=75/25
Flow rate : 0.6mL/min
Detector : UV(254nm)
Column temp. : 30°C