EPR study of effect of ascorbic acid on hair and feather samples in relation to eumelanins and pheomelanins

1, 10 and 100 mM for 24 hours and then dried. The samples were cut into small pieces, put into an EPR measuring tube and the EPR signal was measured. The same procedure was done for control (untreated hair), except that the samples were left in deionised water for 24 hours. To obtain the accurate g values, a manganese ion standard, enclosed in a sealed thin glass tube, was inserted into the EPR tube with the hair/feather sample and the g value of the sample was calculated using the formula [1]: where d is the difference in measured g values between the third and fourth hyperfine lines of the manganese ion standard, r is the difference in measured g values between the