Neutron Activation Analysis of Single Human Hairs and Possible Applications for Forensic Purposes

摘要

A new analytical procedure that enables one to determine more than 10 trace elements in single, 3 cm human hair segments by neutron activation analysis (NAA) was elaborated. Application of a special washing procedure of hair (before irradiation) made it possible to lower sodium content by two orders of magnitude without affecting trace element content. After irradiation in the thermal neutron flux of about 10 exp 14 n.cm exp -2 .sec exp -1 the activity of hair was measured with 70 cm exp 3 Ge(Li) detector coupled to 4000 channel pulse height analyser. As an alternative method, a destructive version of NAA with ion exchange group separation of radionuclides was applied. It was found that sometimes high gradients of element concentration along the hair length exist and that there is without any doubt a distinct influence of environmental factor on the content of some trace elements in hair. The criminalistic aspects of hair analysis were also studied using new statistical criterion for elimination (identification). Both possibilities and limitations of the method are discussed. (Atomindex citation 09:375257)