Identification of firearms holders by the [Fe(PDT)₃] ⁺² complex. Quantitative determination of iron transfer to the hand and its dependence on palmar moisture levels

Quantitative data are reported for the first time on the amounts of iron, which are transferred to the hand upon holding a firearm. Iron levels between 21-315 ng/cm² were found on volunteers' palms after a single holding of a handgun. Determination of the iron traces was accomplished spectrophotometrically using 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT) as a complexing agent. The transfer of iron from firearms to the palm was found to be, by and large a chemical (dissolution) rather than mechanical dislodgement. The prime factor that determines the amount of iron transferred from the firearm to the hand is the moisture level on the palm. These findings are likely to be of importance in courts of law, as well as in the war against terrorism and serious crime.