Ibuprofen and naproxen have been quantified in tablets by capillary isotach
ophoresis. Hydrochloric acid (10 mmol/l) adjusted with creatinine to pH 5.0
plus 0.1% polyvinylpyrrolidone was used as the leading electrolyte and 10
mmol-l 4-morpholineethanesulfonic acid as the terminating electrolyte. Line
arity was observed from 40.0 to 200.0 mg,l of ibuprofen (naproxen), with a
coefficient of determination (r(2)) of 0.999. Good quantitation was obtaine
d in short analysis time. The isotachophoretic results were compared with t
hose obtained by the fluorescence spectrometry. Experimental parameters for
ibuprofen were: lambda (EX) = 224 nm and lambda (EM)= 290 nm. Experimental
parameters For naproxen were. lambda (EX) = 230 nm and lambda (EM) = 355 n
m. The calibration plot was Found to be linear in the range 0.4-2.4 mg,l fo
r ibuprofen and 5.0-20.0 mug/l for naproxen. The minimal sample pretreatmen
t and relatively low running cost make isotachophoresis a good alternative
to existing methods. (C) 2001 Elsevier Science B.V. All rights reserved.