HPLC Analysis of Cosmetic Preservatives on Ascentis^® Express C18 (0.6 mL/min)

column

Ascentis Express C18, 7.5 cm x 3 mm I.D., 2.7 μm particles (53812-U)

mobile phase

[A] water; [B] methanol; (55:45, A:B)

flow rate

0.6 mL/min

column temp.

35 °C

detector

UV, 250 nm

injection

1 μL

sample

methyl-, benzylparaben, 50 mg/L; ethylparaben, 30 mg/L; propyl-, butylparaben, 100 mg/L; 2-phenoxyethanol, 1.5 g/L; 1-phenoxy-2-propanol, 3 g/L; all in 40% methanol