Comparative analysis of hair melanins by chemical and electron spin resonance methods.

Eighteen hair samples from Karakul newborn lambs with various colors were estimated for eumelanin and pheomelanin contents (Ce and Cp, respectively) by electron spin resonance (ESR) spectrometry and by high-performance liquid chromatography (HPLC). Correlation coefficients between the values estimated by the ESR and HPLC methods were 0.96, 0.93, and 0.99 for Ce, Cp, and Ce/Cp, respectively. The high correlation coefficients show that both methods fit well for estimation of relative values of these parameters. The absolute values of Ce and Ce/Cp coincide rather well when Ce is high, but considerable discrepancies appear when Ce is low. The reasons for these discrepancies are discussed. The HPLC method appears to be more sensitive for detection of low concentrations of pheomelanin, while the ESR method fits well for mass selection purposes.