Isotachophoretic determination of naproxen in the presence of its metabolite in human serum

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.