An isotachophoretic method with conductivity detection was developed to det
ermine naproxen in the presence of its metabolite 6-O-desmethylnaproxen in
human serum. The leading electrolyte contained 10 mM hydrochloric acid, bet
a -alanine, pH 4.0 and 0.1% methylhydroxypropylcellulose. The terminating e
lectrolyte was 10 mM 2-(N-morpholino)ethanesulfonic acid-tris(hydroxymethyl
)aminomethane, FK 6.9, containing 20% (v/v) of ethanol. Naproxen was determ
ined in serum supernatant after simple deproteination of the sample with et
hanol. The isotachophoretic results were compared with those obtained by sy
nchronous fluorescence spectrometry. (C) 2001 Elsevier Science B.V. All rig
hts reserved.