Rabbit After The Vitreous Humor Of Change And Time Of Death

Objective:To seek a precise method for estimating postmortem interval (PMJ) in forensic medicine practice. Methods: This study detected the concentration of 21 elements in the vitreous humor of rabbit within 96 hours after death and explored the relationship between their concentration and PMI using the method of ICP-MS. These elements included potassium (K) , Magnesium (Mg) , Sodium (Na) , Zinc (Zn), Nickel (Ni) ,Iron (Fe) , Phosphorus (P) ,Strontium (Sr), Bariuni (Ba) Calcium (Ca) , Aluminium (Al) , Antimony (Sb) , Lead (Pb), Lithium (Li) , Molybdenum (Mo) ,Copper (Cu) ,Cobalt (Co) ,Titanium (Ti) ,Cadmium (Cd) ,Iodine (1) and Bismuth (Bi) And the absorbance was also investigated within 72 hours after death using Model 754spetrophotometer in apt wavelength (420am). Results: It was shown that the concentration of 9 elements and the absorbance in vitreous humor of rabbit within different intervals after death were correlated to PMI available as a reference indicator to estimate PMI. The relationship between PMI and element concentration and the absorbance were: K(within 96h, R2?.9827); Mg(within 48h, R2?0.9119); Na(within 24li. R2=O,9401); Zn (within 24h, R2~0.9202); Ni (within 24h, R20,9103); Fe (within 6-24h. R20.9798; within 24-72h, R2敂O.9938); P (within 12h, R21; within 12-72h, R2=0.9602); Sr (within 12h, R2抣); Ba (within 24-72h~ R2=0.8117): the absorbance of vitreous humor (within 72h, R2=0.9933) .,And the binomial regression formulae of these indices has been worked out. The stepwise regression analysis formulae of the relationship between PMI and K. Mg~ Na, Ni.. Zn concentrations were PMI = 6.7968 + 0.0970K - 0.6067Mg - 0.0084Na + 66,6719Ni 6.0238Zn (within 96h, R2=0.8015) The formulae of the relationship between PMI and K.. P. Na. Ni concentrations were PMI 19.7776 + 0.0334K - 0.0563P - 0.0043Na - 63.1923Ni (within 24h, R2=0.873 1) (In the formulae , the unit of time was hour ; that of the determined concentration of K.. Mg.. Na.. Ni. Zn.. P was mglg) Conclusion : The changes in the concentration of certain elements in vitreous humor and the absorbance of vitreous humor are correlated with PMI and determination of such changes can be used to estimate the time of death.