Abstract: Objective To explored the relationship between the concentration of potassium ion as well as sodium ion in the aqueous humor and post-mortem interval (PMI). Methods The concentrations of potassium ion and sodium ion in the aqueous humor of swine within 48 h after death at 4 ℃ and 28 ℃ were detected using Z-500 atomic absorption spectrophotometer. Results The concentrations of potassium ion and sodium ion in aqueous humor of isolated swine eyeballs within 48 h after death when the environmental temperature was 4 ℃ were significantly related to PMI. The relationship between PMI and the concentration of potassium ion was PMI=-0.178[K+]2+49.978(R2=0.995). The relationship between PMI and the rate of sodium ion and potassium ion was PMI=120.987/[Na+/K+]-28.834(R2=0.905). Conclusion The concentration of potassium in aqueous humor of isolated swine eyeballs may be one of the reference indicators to estimate PMI of the corpses at lower temperatures.

Key words: forensic pathology, aqueous humor, potassium, sodium, postmortem interval estimation, swine