Measuring the water content in freshly-deposited fingermarks

Or Keisar, Yair Cohen, Yacov Finkelstein, Natalie Kostirya, Roey Ben-David, Albert Danon, Ze'ev Porat, Joseph Almog

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The literature view regarding the composition of deposited fingermarks has long been that the average water content is in the range of 98–99 wt.%. This value has recently been challenged by Kent, claiming that it should be 20 wt.% at most. Herein we have measured the weight percentage of water content in freshly-deposited fingermarks, with and without hand pre-washing. Two complementary techniques were utilized for the measurements, namely quartz crystal microbalance (QCM) for determining the relative mass-loss and its rate at ca. 37 °C, and temperature-programmed desorption-mass spectrometry (TPD-MS) for establishing that the mass loss arises solely from the complete evaporation of all the water content in the fingermarks (done with hand pre-washing only). Unlike the traditional narrow-range values of 98–99% and the limiting value of 20 wt.% suggested by Kent, our measurements indicate the occurrence of a broad 20–70% water content. Higher contents of water in fingermarks were found post hand pre-washing, most probably due to removal of the sebum from the fingertips, but none of the results exceeded 90%.

Original languageEnglish
Pages (from-to)204-210
Number of pages7
JournalForensic Science International
Volume294
DOIs
StatePublished - 1 Jan 2019

Keywords

  • Fingermarks
  • QCM
  • Relative mass loss
  • TPD-MS
  • Water content

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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