Flow injection and batch spectrophotometric determination of ibuprofen based on its competitive complexation reaction with phenolphthalein-β-cyclodextrin inclusion complex

Rapid, simple, and accurate spectrophotometric method is presented for the determination of ibuprofen by batch and flow injection analysis methods. The method is based on ibuprofen competitive complexation reaction with phenolphthalein-beta-cyclodextrin (PHP-beta-CD) inclusion complex. The increase in the absorbance of the solution at 554 nm by the addition of ibuprofen was measured. Ibuprofen can be determined in the range 8.0 x 10(-6) -3.2 x 10(-4) and 2.0 x 10(-5) -5.0 x 10(-3) mol l(-1) by batch and flow methods, respectively. The limit of detection and limit of quantification were 6.19 x 10(-6) and 2.06 x 10(-5) mol l(-1) for batch and 1.77 x 10(-5) and 5.92 x 10(-5) mol 1(-1) for flow method, respectively. The sampling rate in flow injection analysis method was 120 +/- 5 samples h(-1). The method was applied to the determination of pharmaceutical formulations.