Study On The Postmortem Production Of Cyanide And Its Metabolites In Preserved Blood

Objective:1.To establish a gas chromatography detection method for CN~-in biological samples,and optimize the ion chromatography detection method of SCN~-and the LC-MS/MS detection method of ATCA;2.To detect CN~-,SCN~-and ATCA in blank blood samples under different preservation conditions,and to observe whether CN~-,SCN~-and ATCA were produced in blank blood samples when puterfaction occurred with the extension of preservation time;3.To detect CN~-,SCN~-and ATCA in blank blood samples,blank blood samples added with potassium cyanide,blood samples of poisoning cases under different preservation conditions,conclude the optimal preservation conditions of suspected cyanide poisoning cases,and to determine the biomarkers of cyanide poisoning.Methods:The content of cyanide in blood samples was detected by derivatization and gas chromatography with electron capture detector.The content of SCN~-was detected by protein precipitation and ion chromatography conductance detector.The content of ATCA was detected by liquid-liquid extraction and LC-MS/MS.The contents of CN~-,SCN~-and ATCA in blood were analyzed from 0 day to 77 days at 20℃,4℃and-20℃.Results:Blood samples stored at different temperatures can produce CN~-,SCN~-and ATCA with the extension of preservation time is extended.Among them,CN~-was produced earliest in blood samples stored at-20℃in 21st day,the highest concentration was 0.193μg/mL;CN~-was produced in blood sample stored at 4℃until 49th day,and the concentration of CN~-was 0.030μg/ml on the 77th day;at 20℃,trace CN~-was detected on the 63rd and77th day.The concentration of SCN~-in blood sample at 20℃was the highest,and the highest concentration was 1620.5ng/mL,which value exceeded the upper limit of the medical reference value of healthy non-smokers;the concentration of SCN~-in the blood sample at4℃increased from 463ng/mL to 967ng/mL;the change SCN~-concentration in the blood sample at-20℃was close to that in the blood sample at 4℃.Blood samples produced the highest concentration of ATCA at 20℃and could be generated on the 21st day.The highest concentration produced was 267.2ng/mL.The change of ATCA concentration in blood samples stored at 4℃and-20℃was relatively small However,the maximum concentration of ATCA in blood without cyanide poisoning will not exceed the upper limit of the medical reference value of healthy non-smokers.The concentration of ATCA in the blood of poisoning cases far exceeds the upper limit of the medical reference value of healthy non-smokers.Conclusion:It is preliminarily inferred that ATCA could be used as a biomarker of cyanide poisoning,and distinguish cyanide poisoning from postmortem production.The best preservation condition for suspected cyanide poisoning cases is that the sample should be sealed in full storage containers and kept below-20℃.