LC Conditions:

Flow Rate:  0.7 mL/min, column temperature
                     40 °C, injection volume 10 μL
Mobile Phase:  90:10 of Methanol / 5 % Acetic Acid
                            in water, isocratic

Post-Column Conditions:
(non-metallic post-column derivatization system is required):

Reagent 1:  Concentrated Sulfuric Acid / Methanol (4:96 v/v)
Reactor 1:  Ambient, 0.1 mL
Reagent 2:  60 g of Vanillin (or p-dimethylaminobenzaldehyde)
                     in 950 mL of Methanol
Reactor 2:  90 °C, 1.4 mL
Reagents Flow Rate:  0.3 mL/min

NOTE: Using 2-reagent system for this application
greatly extends life of reagents.

One-reagent method and post-column derivatization
system are also available.

Detection:

UV-Vis Detector: Vanillin λ=520 nm, DMAB λ=450 nm