Th. Tsai et al., Measurement of hydroxyl radical in rat blood vessel by microbore liquid chromatography and electrochemical detection: an on-line microdialysis study, J CHROMAT B, 734(2), 1999, pp. 277-283
Salicylic acid (0.5 mM) is used as a trapping reagent of hydroxyl radical,
and the formed 2,3- and 2,5-dihydroxybenzoic acids were collected via an on
-line microdialysis device from the blood vessels. This study revealed the
use of a sensitive liquid chromatographic system with electrochemical detec
tion for the determination of 2,3- and 2,5-dihydroxybenzoic acids. Mobile p
hase consisted of 0.1 M monochloroacetic acid, 10 mM EDTA, 0.5 mM sodium oc
tylsulfate, 20% acetonitrile and 5% tetrahydrofuran in 1 l (pH 3.0 adjusted
with 1 M NaOH), and the flow-rate of 0.05 ml/min were found to be optimum.
Isocratic separation of these adducts on a microbore column (reversed-phas
e C-18, 150X1 mm I.D., 5 mu m) was achieved within 10 min. The optimal appl
ied potential of dihydroxybenzoic acids was set at 750 mV based on a hydrod
ynamic study. This method has the detection limits of 1.3 pmol/ml (or 0.2 n
g/ml) for 2,3- and 2,5-dihydroxybenzoic acids in Ringer solution (at signal
-to-noise ratio=3). (C) 1999 Elsevier Science BN. All rights reserved.