HPLC Conditions
Isocratic RPHPLC analysis of tomatoes and tomato-based products
with UV detection was performed by a modification of a method published
elsewhere [20]. Compounds were separated on a 250 mm × 4.6 mm
i.d., 5-µm particle, Hypersil-ODS column (Phenomenex, CA, USA) with
- 198 -25:75 (v/v) acetonitrile–pH 2.4 phosphate buffer (25% acetonitrile in
0.025 M NaH2PO4) as mobile phase at a flow rate of 1.2 mL min
–1.
The HPLC equipment comprised Hewlett–Packard (HP) 1050
ChemStation Software, an HP model 35900 interface unit, an HP 9000
Series 300 computer, and an HP DeskJet 500 Printer. A Waters 486 tunable
absorbance detector was operated at 266 nm; detector sensitivity was
0.05 AUFS and the column oven temperature was 30°C. Determinations
were performed after three separate extractions of each sample, and each
extract was injected in triplicate (n = 3).