HPLC Analysis of Herbal Supplement Containing Milk Thistle on Ascentis^® Express 2.7 μm C18

column

Ascentis Express C18, 10 cm x 3.0 mm I.D., 2.7 μm particles (53814-U)

mobile phase

[A] water with 0.1% formic acid; [B] methanol

gradient

held at 35% B for 3 min; 35 to 45% B in 10 min; held at 45% B for 2 min; 45 to 100% B in 5 min

flow rate

0.6 mL/min

pressure

4105 psi (283 bar)

column temp.

35 °C

detector

UV, 254 nm

injection

20 μL

sample

20 mg/mL in water:ethanol (5:95); sonicate 15 minutes; filter 0.45 μm; dilute to water:ethanol (80:20)