Abstract: Objective To investigate the postmortem distribution of tetrodotoxin in tissues and body fluids of guinea pig, and to provide method and evidence for forensic identification and clinical diagnosis and treatment. Methods Guinea pigs were intragastric administrated with 100, 50, 15 μg/kg tetrodotoxin, respectively. The poisoning symptoms were observed. The samples of heart, liver, spleen, lung, kidney, brain, stomach, intestines, bile, heart blood and urine were collected. The concentrations of tetrodotoxin in tissues and body fluids were measured with liquid chromatography-tandem mass spectrometry（LC-MS/MS）. Results After administrated with tetrodotoxin, all guinea pigs came out poisoning signs including tachypnea, weary and dead finally. Tetrodotoxin concentrations in lung, stomach, intestines and urine were higher, followed by blood, heart and brain. The concentration in bile was the lowest. Conclusion Postmortem distribution of tetrodotoxin in guinea pig is uneven. The concentration in the lung, stomach, intestines, urine and heart blood are higher, those tissues could be used for diagnosis of tetrodotoxin poisoning.

Key words: forensic toxicology, tetrodotoxin, LC-MS/MS, postmortem distribution, guinea pigs