Determination of ketotifen by using calcein as chemiluminescence reagent.

Chemiluminescence (CL) was observed when potassium hexacyanoferrate(III) reacted with the mixture of calcein and ketotifen. Interestingly, the CL intensity would be enhanced by trace amounts of Mg2+ and the CL intensity was strongly dependent on ketotifen concentration. Based on this phenomenon, a flow injection CL method was established for the determination of ketotifen. The possible CL mechanism is proposed based on the kinetic characteristic of the CL reaction, CL spectrum, ultraviolet (UV) spectra and fluorescent spectra. The CL intensity was correlated linearly with concentration of ketotifen over the range of 6.0x10(-9) to 2.0x10(-7) g mL(-1) and the detection limit was 3x10(-9) g mL(-1). The relative standard deviation was 1.8% for 2.0x10(-8) g mL(-1) ketotifen (n=11). This method was applied to the determination of ketotifen in the tablets successfully.