UHPLC Analysis of Bisphenol A and Analogous Compounds in Infant Formula on Titan C18 with Fluorescence Detection after SPE using SupelMIP^® Bisphenol A

sample/matrix

liquid infant formula

SPE well plate

SupelMIP Bisphenol A, 100 mg/3 mL (52775-U)

condition

3 mL 2% formic acid in methanol, 3 mL acetonitrile, 3 mL water

sample addition

as prepared

washing

9 mL of water, 6 mL of acetonitrile:water (40:60); vacuum was pulled for 3 min after the last wash

eluate post-treatment

Sample was evaporated to dryness at 45 °C, reconstuituted in 0.5 mL of acetonitrile:water (40:60). All samples were filtered through Durapore membrane filter units prior to analysis.

column

Titan C18, 10 cm x 2.1 mm I.D., 1.9 μm particles (577124-U)

mobile phase

[A] water; [B] acetonitrile

gradient

40 to 80% B in 2.5 min; held for 4.5 min; to 100%B in 0.1 min; held for 2.4 min; to 40% B in 0.1 min; held for 2.9 min

flow rate

0.25 mL/min for 7 min; to 0.40 mL/min in 0.1 min; held for 2.4 min; to 0.25 mL/min in 0.1 min.; held for 2.9 min

pressure

3916 psi (270 bar)

column temp.

35 °C

detector

fluorescence, ex: 230 nm, em: 315 nm

injection

5 μL

elution

3 mL of methanol:acetonitrile (75:25) (A017)