Human scalp hair that had not been permed or dyed was collected from Vietnamese males in a barbershop in Hanoi between June and September in 2016. The total quantity of hair (10 kg) was washed well by hand five times in a 0.3% neutral detergent. The detergent was removed using tap water and then rinsed out with distilled water. The clean hair was dried in an oven at 60°C overnight. The dried hair was pulverized by the combined action of a roll crusher, pin mill and air-jet mill to particles with a size below 74 µm. After rigorous blending, three gram aliquots of the homogenized hair powder were poured into borosilicate bottles and sterilized by gamma-irradiation.
keywords: biological materials , human tissue , hair , trace elements , heavy metals , mercury speciation , speciation analysis , organometallics