Experimental study on age estimation of fingermarks / 中国法医学杂志

ABSTRACT

Objective The content of urea and amino acids in sweat fingerprints is examined by ultraviolet spectrophotometry at ambient temperature of 25 and relative humidity of 65%. Methods In the fingerprint of sweat, urea and amino acids are chemically reacted to produce blue and blue purple matter.Their concentrations are calculated by ultraviolet spectrophotometerand the two ratios are calculated to infer the remaining time. Results Left time of sweat fingerprints shows a linear correlation with urea and amino acid ratio, the linear regression equation is Y=-3.227X+6.706, the female is Y=-3.672X+6.546, the regression equation is Y=-3.276X+6.638.Conclusion The remaining time of human sweat fingerprints is linearly related to the ratio of urea to amino acidsand the regression relation can be used to infer the time of fingerprint retention.