Abstract
A rapid, simple and highly sensitive flow-injection (FI) electrogenerated chemiluminescence (ECL) method was developed for the determination of melanin, a biological pigment present in the skin, eyes, hair, scales and it is responsible for color of them. The proposed method was based on the ECL reaction of Ru(bpy)(3)(2+) with melanin in an acidic medium. The different experimental parameters affecting the ECL intensity were carefully studied and incorporated into the procedure. The method permits the determination of 0.01 - 2.0 mu g mL(-1) and 3.0 - 35 mu g mL(-1) of melanin with correlation coefficients (r) > 0.9999. The lower limit of detection (LOD) is 0.0005 mu g mL(-1) (S/N = 3) and the lower limit of quantitation (LOQ) is 0.01 mu g mL(-1). The proposed method was successfully applied to the determination of melanin in Sepia Officinalis and natural samples.