Flow-injection determination of vitamin A in pharmaceutical formulations using Tris(2,2′-bipyridyl)Ru(II)-Ce(IV) chemiluminescence detection

A flow injection method with chemiluminescence detection is reported for the determination of vitamin A. The method is based on the enhancement effect of vitamin A on chemiluminescence of tris(2,2'-bipyridyl)Ru(II)-Ce(IV) in acidic medium. The proposed procedure is used to quantitate vitamin A in the range 1.0-100 x 10(-6) mol/L with a correlation coefficient of 0.9991 (n = 9) and relative standard deviation in the range 1.2-2.3% (n = 4). The limit of detection (3 x blank) was 8.0 x 10(-8) mol/L with a sample throughput of 100/h. The effect of common excipients used in pharmaceutical formulations and some clinically important compounds was also studied. The method was applied to determine vitamin A in pharmaceutical formulations and the results obtained were in reasonable agreement with the amount quoted. The results were compared using spectrophotometric method and no significant difference was found between the results of the two methods at 95% confidence limit. Copyright (C) 2009 John Wiley & Sons, Ltd.