LC/MS Analysis of Omeprazole and Metabolites on Ascentis^® Express RP Amide (pH 3.4)

column

Ascentis Express RP-Amide, 5 cm x 2.1 mm I.D., 2.7 μm particles (53911-U)

mobile phase

[A] 10 mM ammonium formate in water, pH 3.4; [B] 10 mM ammonium formate in methanol, pH 3.4; (65:35, A:B)

flow rate

0.3 mL/min

column temp.

35 °C

detector

ESI(+), m/z 50-400

injection

1 μL

sample

1 mg/L in mobile phase