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A New Method for Determination of Postmortem Interval: Citrate Content of Bone


  • Research supported by grants to HPS from the Social Sciences and Humanities Research Council and the Natural Sciences and Engineering Research Councils of Canada.

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Henry P. Schwarcz, Ph.D.
University Professor Emeritus
School of Geography and Earth Sciences,
McMaster University
Hamilton, ON L8S 4K1


Abstract:  Few accurate methods exist currently to determine the time since death (postmortem interval, PMI) of skeletonized human remains found at crime scenes. Citrate is present as a constituent of living human and animal cortical bone at very uniform initial concentration (2.0 ± 0.1 wt %). In skeletal remains found in open landscape settings (whether buried or not), the concentration of citrate remains constant for a period of about 4 weeks, after which it decreases linearly as a function of log(time). The upper limit of the dating range is about 100 years. The precision of determination decreases slightly with age. The rate of decrease appears to be independent of temperature or rainfall but drops to zero for storage temperature <0°C.

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