Study On The Evaluation Of Qualitative Results Of Pesticides And Benzodiazepines By GC-MS In Forensic Toxicological Analysis

Objective: 1.To establish a method of gas chromatography mass spectrometry(GC-MS)for the simultaneous detection of dichlorvos and phorate,and the simultaneous detection of diazepam and estazolam in human blood.2.To study the maximum allowable deviation of phosphorus pesticides(dichlorvos,phorate)and antipsychotic drugs(diazepam,estazolam)qualitative parameters(retention time and ion ratio)in GC-MS full scan mode to to verify the reliability of the existing guidance document.Methods: 1.Extraction and analysis method: Liquid liquid extraction was used to extract and the effects of different extraction solvents on drug recovery were analyzed.Finally,ethyl acetate was selected as the extraction solvent.2.Statistical methods and other software: SPSS-20.0 software was used for data analysis and Graph Pad Prism 6 was used for drawing.Results: 1.Detection of pesticides(dichlorvos,phorate and internal standard tributyl phosphate)and benzodiazepines(diazepam,estazolam and internal standard SKF525A)by using GCMS full scan mode.The linearity of dichlorvos and phorate were 0.5-20.0 ?g/m L,R2 were 0.9989 and 0.9987,respectively,and the limit of quantification(LOQ)were 0.16 ?g/m L and 0.14 ?g/m L,respectively.The linearity of diazepam and estazolam were 0.2-20.0 ?g/m L,R2 were 0.9989 and 0.9987,respectively,and the limit of quantification(LOQ)were 0.11 ?g/m L and 0.10 ?g/m L,respectively.2.In the full scan mode of GCMS-TQ8030,the retention time of pesticides(dichlorvos,phorate and internal standard tributyl phosphate)and benzodiazepines(diazepam,estazolam and internal standard SKF525A)were stable in different concentrations.In the full scan mode of 7890A-5875 C,the retention time of pesticides(dichlorvos,phorate and internal standard tributyl phosphate)were were stable in different concentrations.The maximum tolerance deviation of RT was ±0.05 min,and the maximum tolerance deviation of RRT was ±0.5%.3.The reference value of ion ratio of pesticides(dichlorvos,phorate and internal standard tributyl phosphate)and benzodiazepines(diazepam,estazolam and internal standard SKF525A)in the full scan mode of GCMS-TQ8030 were 79/109=0.30 ?185/109=0.26 ? 145/109=0.08 ? 121/75=0.33 ? 97/75=0.225 ? 231/75=0.10 ?283/256=0.935 ? 221/256=0.59 ? 165/256=0.2 ? 205/259=0.53 ? 293/259=0.37 ?239/259=0.35,respectively.The reference value of ion ratio of pesticides(dichlorvos,phorate and internal standard tributyl phosphate)in the full scan mode of 7890A-5875 C were 79/109=0.20 ? 185/109=0.315 ? 145/109=0.09 ? 121/75=0.405 ? 97/75=0.28 ?231/75=0.11.The maximum tolerance deviation of ion ratio were ±10%(absolutely)and ±25%(relatively).In the lower concentration or lower S/N,the maximum tolerance deviation of ion ratio can be increased to ±50%(relatively).Conclusion: 1.This study established a simultaneous detection of dichlorvos,phorate,diazepam and estazolam in human blood by liquid-liquid extraction and GC-MS,which could be used for forensic identification of these drug poisoning cases.2.In the fortified of dichlorvos,phorate,diazepam and estazolam in human blood,the absolute deviation of RT can be relaxed to less than ±0.05 min or 3 s,and the relative standard of RRT can be relaxed to less than ±0.5%.In the case of lower concentrations,RRT is recommended.Because the deviation of RRT is smaller and more reliable than RT in these circumstances.3.The maximum allowable deviation of the ion ratio is discussed from signal-tonoise.The criteria of absolute deviation of ion ratio is ±10%.,and the relative deviation is ±25%.The relative deviation should be increased to± 50% at lower concentration or lower S/N.But there is still need the experienced forensic analysts to check the data carefully before they can get the final conclusion.