A Flow Injection Chemiluminescence Method for the Determination of Retinol in Pharmaceutical Formulations by Using Luminol-Diperiodatoargentate(III) Reaction

In this paper, a chemiluminescence (CL) method is proposed for retinol determination by combining flow injection (FI) methodology. The CL reaction is based on the oxidation of luminol by diperiodatoargentate (III) (DPA) in the presence of retinol. Under the optimum conditions, the relative CL intensity was linear to the concentration of retinol over the range 5.0X10(-3)-14 mg L-1 (y=347.26x+2.5944, R-2 =0.9999, n=8) with limit of detection (LOD) of 1.5 x 10(-3) mg L-1 (S/N= 3) and limit of quantification (LOQ) of 5.0X 10(-3) mg L-1 (S/N=10). The relative standard deviation (RSD) was from 1.04-3.4% over the range studied and injection throughputs of 150 h(-1). The method was satisfactorily applied to retinol in pharmaceutical formulation samples. The samples were saponified and extracted with liquid-liquid extraction using ether as an extractant. The possible CL mechanism is supported by CL and UV-visible spectrophotometric studies.