【作者】 孙其然；

【导师】 沈敏； 向平； 刘伟；

【作者基本信息】 复旦大学 ， 法医毒化， 2010， 硕士

【摘要】 近年来,麻醉抢劫、迷奸等案件的数量不断增加,如何解决这类案件的分析和举证问题迫在眉睫。在这类案件中,犯罪分子利用一些精神活性物质(包括中枢神经系统抑制剂、兴奋剂和致幻剂等),或使人失去知觉,或使人变得亢奋、行为失控,防御能力降低等,以便于他们实施抢劫或性侵犯。等被害人清醒报案时,常常已是案发后几个小时甚至几天了；而这些精神活性物质的用药剂量小、体内代谢速度快,因此取得的血样和尿样往往已无法提供有效的摄药证据。毛发样品在法庭毒物分析领域有独特的应用价值,它能够反映长程用药信息,而且易采集、易保存。在麻醉抢劫和迷奸案的分析、定性中,毛发能够作为血液和尿液的补充,提供被鉴定人的用药史。但是,麻醉抢劫和迷奸案都属于单次用药的案件,毛发中能检测到的目标物浓度仅在pg/mg级,且毛发基质成分复杂——这些特点要求所建的分析方法必须灵敏度高、选择性强。液相色谱-串联质谱(LC-MS/MS)技术近年来发展迅速,它分析范围广,而且样品不需衍生化,前处理简便；采用多反应监测(multiple reaction monitoring, MRM)模式,更可大大提高分析方法的选择性和灵敏度。本课题在原有的研究基础和分析技术的前沿上,建立头发中54种精神活性物质的LC-MS/MS筛选方法；以目前涉案较多的精神活性物质艾司唑仑、三唑仑、氯胺酮和可卡因为目标物,通过动物实验或者志愿者实验,进行单次用药后的毛发分析及评价研究。主要的研究内容包括以下5个部分：1.头发中痕量精神活性物质的LC-MS/MS筛选分析建立了头发中54种精神活性物质的筛选体系,包括初步筛选和确证分析。初筛方法选取各目标物的一对母离子／子离子对进行监测,若出现可疑色谱峰,则进一步进行确证分析。确证分析包括5个不同的方法。每个方法都只监测特定种类的精神活性物质(阿片类、氯胺酮及苯丙胺类、可卡因类、苯二氮(?)类和其它),并选取两对母离子／子离子对来确认目标物。通过增加离子对驻留时间(Dwell time)来提高方法的灵敏度,从而能够对头发中痕量的精神活性物质进行分析。2.单次用药后头发中苯二氮(?)类药物的分析及评价研究建立了头发中18种苯二氮(?)类药物的LC-MS/MS分析方法,各目标物的最低检测限在0.5-5pg/mg的范围内。应用该方法对单次服用艾司唑仑的14名志愿者的头发进行分段分析,发现：用药后一个月,艾司唑仑的浓度峰值出现在0-2cm的头发段中；头发中的艾司唑仑浓度与服药剂量有一定相关性,检测的剂量阈值大约为1mg。此外,将本方法应用于实际迷奸案件,从被鉴定对象头发中检出了氯硝西泮和代谢物7-氨基氯硝西泮。3.单次用药后毛发中三唑仑及其代谢物的分析及评价研究建立了毛发中三唑仑及α-羟基三唑仑的LC-MS/MS分析方法,三唑仑的最低检测限为1pg/mg,代谢物α-羟基三唑仑的最低检测限为5pg/mg,它们分别在2～200pg/mg和10～500pg/mg范围内线性良好。18只豚鼠分成三组,按10μg/kg、100μg/kg和500μg/kg的剂量分别给予三唑仑灌胃一次。给药前,剃去豚鼠背部的毛发；给药后每隔7天收集一次新生毛发,连续5周。结果表明：三唑仑和α-羟基三唑仑只能在给药后第1周收集的毛发样品中检出；α-羟基三唑仑的浓度高于三唑仑的浓度；黑色毛发中的目标物浓度高于棕色和白色中的；毛发中检出的目标物浓度和给药剂量有一定的相关性,可以检出三唑仑的最小剂量大约为100μg/kg。4.单次用药后毛发中氯胺酮及其代谢物的分析及评价研究建立了毛发中氯胺酮及去甲氯胺酮的LC-MS/MS分析方法,氯胺酮的最低检测限为0.5 pg/mg,去甲氯胺酮的最低检测限为1pg/mg,它们在2～200pg/mg范围内线性良好。18只豚鼠分成三组,按20μg/kg、100μ/kg和1mg/kg的剂量分别给予氯胺酮灌胃一次。给药前,剃去豚鼠背部的毛发；给药后每隔7天收集一次新生毛发,连续5周。结果表明：在给药后第1、2周内收集的毛发样品中能检出氯胺酮和去甲氯胺酮,其中以第1周收集的毛发中的目标物浓度为高；氯胺酮的浓度高于去甲氯胺酮的浓度；黑色毛发中目标物的浓度高于棕色和白色中的；毛发中检出的目标物浓度和给药剂量有一定的相关性,可以检出氯胺酮的最小剂量大约为100μg/kg。在动物实验的基础上又进行了志愿者实验：4名志愿者口服10mg氯胺酮,给药后第1、2、3、4、8、12、16周采集头发样品,进行分段分析。结果表明：给药后第1周采集的头发中即可检出氯胺酮和去甲氯胺酮,直至第16周仍可检出；氯胺酮的浓度峰值在毛干中以1-1.5cm/月左右的速度向后移动；部分头发样品中去甲氯胺酮的浓度高于氯胺酮的浓度；目标物在头发中存在纵向扩散,提示目标物可能经汗液、皮脂分泌等多种途径进入头发。5.单次用药后毛发中可卡因及其代谢物的分析及评价研究建立了毛发中可卡因及苯甲酰爱康宁的LC-MS/MS分析方法,可卡因和苯甲酰爱康宁的最低检测限都为2.5pg/mg,分别在10～250pg/mg和5～250pg/mg范围内线性良好。8只豚鼠分为两组,分别以10mg/kg和0.4mg/kg的剂量腹腔注射盐酸可卡因水溶液一次。给药前,剃去豚鼠背部的毛发；给药后第7天和第14天收集新生毛发。结果表明：给药后第7天收集的毛发中的目标物浓度较高,能同时检出可卡因和苯甲酰爱康宁,第14天收集的毛发样品中仅检出可卡因：可卡因的浓度高于苯甲酰爱康宁的浓度；黑色毛发中目标物含量比棕色和白色中的高；10mg/kg剂量组的毛发中检出的目标物浓度高于0.4mg/kg组的。通过上述研究,本课题(1)建立了头发中54种精神活性物质的LC-MS/MS系统筛选分析体系。该体系灵敏度高,选择性强。通过志愿者实验和实际案例应用,证明该体系能够解决头发中痕量未知精神活性物质的分析和确认问题。(2)阐明了单次用药后三唑仑、氯胺酮和可卡因在豚鼠毛发中的时间过程,药物原体和代谢物在毛干中的分布,以及给药剂量、毛发颜色对目标物浓度的影响,基本确立了这三种精神活性物质在豚鼠毛发中的最小检出剂量。(3)确立了单次用药后头发样品的采集时间和采集方法,考察了分段分析在单次用药结果判断中的适用性。更多还原

【Abstract】 Drug-facilitated crimes (DFC) refer to the use of a drug to modify a person’s behavior for criminal gain. Drugs used to facilitate crimes can be difficult to detect (active products at low doses, chemical instability), possess amnesic properties and can be rapidly cleared from the body (short half-life). In these situations, blood or even urine can be of low interest. In contrast, hair analysis boasts longer detection window, thus hair was suggested as a valuable specimen in situations where, as a result of a delay in reporting the crime, natural processes have eliminated the drug from typical biological specimens. However, hair analysis after a single dose requires more sensitive and selective methods, which needs to be carried out by tandem mass spectrometry.Liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology has developed rapidly in recent years. It analyzes a wide range of chemicals without derivatization. Selectivity and sensitivity are greatly improved under multiple reaction monitoring (MRM) mode.Based on the published literatures and with the help of advanced analytical technology, we have finished a series of studies focusing on hair analysis after a single dose. The major results and conclusions are listed as follows:1. Screening for drugs involved in DFC in hair with LC-MS/MSAn LC-MS/MS method screening for 54 drugs involved in DFC in hair has been established. The screening system included two steps:at first, each analyte was monitored with one pair of precursor/product ion. When a peak of interest appeared, a following specific method including two ion pairs for each analyte (screening for opiates, amphetamine and ketamine, cocaine, benzodiazepines or other drugs respectively) would be used to confirm the suspecting analyte. By increasing the dwelling time of each pair of ions, the sensitivity of the method was greatly improved and thus adequate to detect trace drugs in hair.2. Evaluation of segmental hair analysis after a single dose of benzodiazepinesSensitive, specific, and reproducible methods for the quantitative determination of 18 benzodiazepines in hair have been developed using LC-MS/MS. LOD (limit of detection) for 18 bezodiazepines range from 0.5pg/mg to 5pg/mg.14 volunteers had ingested a single 1-6mg estazolam tablet. Hair was collected one month after administration and analyzed with the screening method. All the proximal segments were positive for estazolam. The concentration of estazolam detected in hair correlated with the given dosages.The minimal dosage of estazolam detectable in hair was about lmg. The screening method was also applied to two authentic drug-facilitated assualts. Full-length hair samples were collected 5 weeks after the offense. Clonazepam and 7-aminoclonazepam were detected in the proximal hair segment.3. Determination of triazolam and a-hydroxytriazolam in hair after a single doseA sensitive LC-MS/MS method is presented for determination of triazolam and a-hydroxytriazolam in guinea pig hair after a single dose. LOD for triazolam and a-hydroxytriazolam were lpg/mg and 5pg/mg respectively. Eighteen guinea pigs were divided into three dosage groups (10μg/kg,100μg/kg and 500μg/kg) and administrated a single dose of triazolam intragastrically. Before administration, drug-free hair was shaved from their back. Newly grown hair in shaved area had been collected every seven days after administration for 5 weeks. Triazolam and a-hydroxytriazolam could only be detected in hair samples collected in the first week. a-Hydroxytriazolam had a higher concentration than triazolam in guinea pig hair. The concentration of triazolam in hair was related with administration dosage and hair color.100μg/kg was the minimal dosage detectable in guinea pig hair.4. Determination of ketamine and norketamine in hair after a single doseA sensitive LC-MS/MS method is presented for determination of ketmaine and norketamine in guinea pig hair after a single dose. LOD for ketmaine and norketamine were 0.5pg/mg and lpg/mg respectively. Eighteen guinea pigs were divided into three dosage groups (20μg/kg,100μg/kg and 1mg/kg) and administrated a single dose of ketamine hydrochloride intragastrically. Before administration, drug-free hair was shaved from their back. Newly grown hair in shaved area had been collected every seven days after administration for 5 weeks. Ketamine and norketamine could be detected in first two weeks. Ketamine had a higher concentration than norketmaine in guinea pig hair. The concentration of ketamine in hair was related with given dosage and hair color.100μg/kg was the minimal dosage detectable in guinea pig hair.A further volunteer experiment has been carried out.4 female volunteers took a single 10mg of ketamine orally. Scalp hair samples were collected 1,2,3,4,8,12 and 16 weeks after the administration. The window of detection was as long as 16 weeks.The results showed that the peak concentration of ketamine moved along the hair shaft at a speed of 1-1.5cm/month. In some proximal segments, the concentration of norketamine was higher than ketamine and target analytes could be detected in other hair segments apart from the corresponding one. These facts indicated that sweat and sebum may be possible sources of drugs incorporated into hair. 5. Determination of cocaine and benzoylecgonine in hair after a single doseA sensitive LC-MS/MS method is presented for determination of cocaine and benzoylecgonine in guinea pig hair after a single dose. LOD for cocaine and benzoylecgonine was 1pg/mg. Guinea pigs were administrated a single dose of cocaine (10mg/kg or 0.4mg/kg, n=4) intraperitoneaklly. Before administration, drug-free hair was shaved from their back. Newly grown hair in shaved area was collected on the 7th and 14th day after administration. Both cocaine and benzoylecgonine could be detected on the 7th day. Additionally, there was a higher concentration of cocaine than that of benzoylecgonine occurred in hair. Concentrations of cocaine and benzoylecgonine detected in hair were related with given dose and hair color.In conclusion, this study (1) established a screening system for the simultaneous determination of 54 drugs involved in DFC case in hair. The screening method has been proved sensitive enough to detect and confirm trace drugs in hair by successful application in cotrolled experiment and real case. (2) demonstrated the time course of triazolam, ketamine and cocaine in guinea pig hair. The distribution of these analytes and their metabolites in hair, and the effects of given dosage and hair color on analytes concentration were also clarified. Besides, the minimal dosages of these analytes detectable in guinea pig hair were basically addressed. (3) established guidelines for hair sample collection after a single administration, and examined the role of segmental analysis in discriminating single exposure from repeated one.更多还原