An established experimental procedure for analyzing the TAC
values of Citrus fruits using the on-line HPLC-FRSD system was as
follows: (1) Sample preparation. The solid dried material
(0.250 mg–0.625 mg) or juice (2.00 mL) of Citrus sample was transferred
into a 50 mL falcon tube added 80% methanol to 25 mL,
mixed well and the tube was put into a shaker overnight at
25 C. The extracts were centrifuged at 5000 g for 10 min on the
next day. The supernatant was then filtered through a 0.22 lm
organic membrane before analysis. (2) Elution of phenolic compounds
using HPLC system. 25 lL of each sample was injected into
the on-line HPLC-FRSD system. The positive chromatographic
peaks of compounds in the samples were separated by Waters
e2695 HPLC system with a Waters X-Terra MS C18 guard column
(3.9 mm 20 mm, 5 lm).