自动顶空GC/MS测定血液中乙醇含量不确定度评定

目的评定自动顶空—气相色谱—质谱法(GC/MS)测定血液中乙醇含量的不确定度。方法从分析测量过程着手,依据不确定度评定的指导性文件,分析了不确定度来源,量化不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度。结果血液样本两次测定结果平均值为0.738mg/mL的扩展不确定度为0.084mg/mL。结论血液中乙醇含量的不确定度主要来源于样品检测、乙醇标准溶液和标准曲线。     

GC/MS测定尿液中氯胺酮含量不确定度评定

目的评定气相色谱—质谱法（GC/MS）测定尿液中氯胺酮含量的不确定度。方法依据不确定度评定的指导性文件,从测定程序分析了不确定度的来源,量化不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度。结果尿液检材中测定结果平均值为0.257μg/mL的扩展不确定度为0.016μg/mL。结论尿液中氯胺酮含量的不确定度主要来源于标准品纯度和标准曲线。     

氢化物原子荧光法测定人发中砷含量的不确定度评定

目的评定氢化物原子荧光法测定人发中砷含量的不确定度。方法以人发标准样品为分析对象,依据化学分析中不确定度的评估指南等指导性文件,分析测定过程中砷含量测定值（C）、样品处理后的总体积（V）、样品称量值（m）以及重复测量（rep）等多个不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度。结果本文方法测定人发中砷含量的不确定度评定结果为：人发样品中砷的含量为（0.57±0.06）mg/kg,置信概率（p）=95%,自由度（υeff）=4。结论本文方法测量不确定度的主要来源是重复性和校准曲线,测定结果在标准物质给出的含量范围之内。     

毛发中甲基苯丙胺含量的测量不确定度评定

对涉嫌吸毒人员毛发样本中的甲基苯丙胺含量进行测量不确定度评定。将毛发样本清洗、定量称取、研磨提取后，采用液相色谱-串联质谱仪（LC-MS/MS）分析甲基苯丙胺含量。基于样本处理程序及外标单点定量法数学模型，分析毛发中甲基苯丙胺含量的不确定度来源，并进行分量评定及合成不确定度计算。本方法检测毛发中甲基苯丙胺含量为0.264 ng/mg，结果的合成相对不确定度为4.0%，引入各项不确定度分量的因素贡献大小顺序为：甲基苯丙胺标准工作溶液浓度>检测重复性>标准工作溶液移取体积>提取溶剂移取体积>检材称取质量。本研究从人员操作、仪器设备和实验环境等方面评定了毛发中甲基苯丙胺含量的不确定度，提高了检验结果科学性和表述严谨性，有利于为涉毒案件的执法和审判提供坚实科学证据。     

顶空气相色谱内标法测定人血中乙醇含量的不确定度评定

目的建立顶空气相色谱内标法测定人血中乙醇含量的不确定度评定的方法。方法结合顸空法乙醇含量测定的全部过程,假设传播系数为1,则对产生不确定度的各分量因子进行分析计算与合成。结果不确定度因素的来源主要包含样品检测时产生的误差值、检测仪器的精密度、使用标准物质的标示值的不确定度和使用的量器、容量器皿等的不确定度。结论本评定方法得出检测的最大误差来自于两个平行样品检测时所产生的误差值。     

直接进样气相色谱内标工作曲线法测定血液中乙醇的不确定度评估

测量不确定度的评估是评价测量结果的有效方法，是测量结果质量的定量表征，是实验室认可评审的重要内容。近年来，实验室认可评审在公安系统陆续开展，我所也于去年10月份通过CNAS认可，在认可过程中进行了血液中乙醇定量项目的不确定度评估。本文以此为例，探讨血液中乙醇含量气相色谱内标法检测结果的不确定的评估过程，以保证检测数据更加准确可靠、有效。     

顶空气相色谱法检测生物检材中乙醇及其相关物质

目的建立生物检材中乙醇及其相关物质的检测方法。方法生物检材加入内标异丙醇后用顶空气相色谱法进行检测(FID检测器),以保留时间定性,内标法定量。结果该方法线性范围为0.05035～1.613mg/ml,相关系数r=0.9999,最低检测限(limit of detection,LOD)为3.379μg/ml,分析方法平均回收率为98.24%～106.5%,日内精密度RSD<2.2%,日间精密度RSD<1.4%,总分析时间不超过18min。结论该方法可用于生物检材中乙醇及其相关物质的检测。     

血液乙醇检测内外标法比较研究

目的通过比较内标法和外标法对血液乙醇含量检测结果,探讨外标法在法医学实践中的应用价值。方法通过收集2005年10月~2006年12月间本中心符合检测要求的血液样品263例,每例分别采用内标法和外标法进行血液样品乙醇含量检测,比较其检测结果。结果外标法检测时间短(2.5min),用量0.5ml,而内标法检测时间长(6.5min),样品量1.0ml;外标法检测血乙醇平均浓度为89.30mg/100ml,内标法检测血乙醇平均浓度为92.37mg/100ml,P=0.001。结论外标法检测时间短(2.5min),用量少,节约检材,可作为大量待测血液样本的筛选检查手段。     

顶空气相色谱法测定血液中乙醇不确定度的评估

目的 评估血液中乙醇测定结果的不确定度。方法 用顶空气相色谱法测定血液样本中乙醇质量浓度,从测定程序分析测量不确定度的来源,计算测定结果的不确定度。结果 血液样本中乙醇质量浓度两次测定平均值为1.00mg/mL,扩展不确定度为0.02 mg/mL。结论 血液中乙醇测定结果的不确定度主要来源于平行测定的误差。     

人体内乙醇含量检测的影响因素分析

人体内乙醇含量检测不仅是法医鉴定工作中常规检测项目,也是交通肇事案件最终的仲裁依据,其检测结果直接影响着受检人员的责任判罚。本文根据乙醇的毒理特征及在人体内的代谢过程,就不同检材、送检时效性、尸体腐败、血液检品中不同成分和保存方式、以及检测结果的不确定度等对乙醇含量检测结果的影响进行分析,以利于对受检者是否饮酒及其程度做出科学、公正的判定。     

直接进样气相色谱法测定全血中乙醇的含量

目的建立一种直接进样气相色谱法检测全血中的乙醇。方法全血经硫酸铝钾沉淀蛋白,加入内标异丙醇后,用直接进样气相色谱法进行检测,FID为检测器,用保留时间定性,内标标准曲线法定量。结果该方法线性范围为0.2-1.4mg/m L,相关系数R=0.999 3,总分析时间不超过5min,最低检测限为0.01mg/m L,相对标准偏差（RSD）〈5%,平均回收率为92.3%;所建立的方法与顶空气相色谱（HS-GC）法比较相对偏差（RD）〈10%。结论该方法可用于全血中乙醇的检测。     

Stability of blood carbon monoxide and hemoglobins during heating

The effects of heating on hemoglobin (Hb) and carbon monoxide (CO) levels in human blood were investigated by in vitro experiments. Head-space gas chromatography (HS-GC) using a molecular sieve 5A stationary phase and thermal conductivity detection was adopted for the measurement of CO gas, and spectrophotometric methods were used for the measurement of various Hb forms, protein and heme contents. Deteriorated absorbance spectra were observed for heat-treated blood samples, and double wavelength spectrophotometry was proven to give wrong percent saturation of carboxyhemoglobin content (% CO-Hb). The blood sample taken from one fatal fire casualty gave significantly higher % CO-Hb measured spectrophotometrically, compared to that by HS-GC. Control blood or purified Hb solution, which was saturated with CO in designated extent, was heated in a sealed vial. Under the incubation below 54 degrees C, all Hb forms were stable, except for oxyhemoglobin (Hb-O(2)), which was partially oxidized to met-hemoglobin (Met-Hb). In contrast, under the incubation at 65 degrees C, Met-Hb was denatured completely to be insoluble, and Hb-O(2) was partially denatured via Met-Hb formation. CO-Hb was resistant against heating. The difference of heat susceptibility and precipitability among Hb forms resulted in artificial increase of % CO-Hb. During heating, spontaneous CO was produced from blood.     

Computer-aided headspace gas chromatography applied to blood-alcohol analysis: importance of online process control

This paper describes the analysis of ethanol in blood specimens from suspect drunk drivers and the associated quality assurance procedures currently used in Sweden for legal purposes. Aliquots of whole blood from two separate Vacutainer tubes are diluted with 1-propanol as internal standard before analysis by headspace gas chromatography (HS-GC) with three different stationary phases: Carbopak B, Carbopak C, and 15% Carbowax 20 M. The actual HS-GC analysis, the integration of chromatographic peaks, the collection and processing of results, as well as the quality control tests involve the use of computer-aided techniques. The standard deviation of analysis(y) increased with concentration of ethanol in the blood specimen(x), and above 0.50 mg/g the regression equation was y = 0.0033 + 0.0153x. The prosecution blood-alcohol concentration (BAC) is the mean of three separate determinations made by different laboratory technicians working independently with different sets of equipment. A deduction is made from the mean analytical result to compensate for random and systematic errors inherent in the method. At BACs of 0.5 and 1.5 mg/g, which are the statutory limits in Sweden, the allowances currently made are 0.06 and 0.09 mg/g, respectively. Accordingly, the reduced prosecution BAC is less than the actual BAC with a statistical confidence of 99.9%.     

Measurement of Uncertainty for Aqueous Ethanol Wet‐Bath Simulator Solutions Used with Evidential Breath Testing Instruments

Aqueous ethanol wet‐bath simulator solutions are used to perform calibration adjustments, calibration checks, proficiency testing, and inspection of breath alcohol instruments. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a measurement of uncertainty for the preparation and testing of these wet‐bath simulator solutions. The measurand is identified as the mass concentration of ethanol (g/100 mL) determined through dual capillary column headspace gas chromatography with flame ionization detector analysis. Three groups were used in the estimation of the aqueous ethanol wet‐bath simulator solutions uncertainty: GC calibration adjustment, GC analytical, and certified reference material. The standard uncertainties for these uncertainty sources were combined using the method of root‐sum‐squares to give u_c = 0.8598%. The combined standard uncertainty was expanded to U = 1.7% to reflect a confidence level of 95% using a coverage factor of 2. This estimation applies to all aqueous ethanol wet‐bath simulator solution concentrations produced by this laboratory.     

Quantification of propane in biological materials by head-space GC

Propane was measured in specimens taken from two persons who died from a LPG explosion in an apartment using head-space-GC/FID. Because of the variation of instrument performance and sample injection, the internal standard pentane was used. Calibration standards were prepared by injecting each calculated volume of pure propane gas into capped vials containing 2 ml of blood and 5 microl of internal standard. The calibration curve revealed good linearity from 0.09 microg/ml to at least 90 microg/ml. The method validation data also included repeatability and recovery. The propane quantities in blood, fat and brain tissue were between 0.27 and 71 microg/ml (microg/g) with the highest concentration observed in fat. The confirmation of propane was conducted by the means of solid phase micro-extraction and mass spectrometry.     

Automated headspace solid-phase microextraction and capillary gas chromatography analysis of ethanol in postmortem specimens

Solid-phase microextraction (SPME) is a relatively new solventless sample preparation technique that allows simultaneous sampling, extraction, pre-concentration, and introduction of analytes from a sample matrix in a single procedure. This methodology has been used for the analysis of several drugs of forensic toxicology interest including volatile compounds. This paper describes a methodology for analysis of ethanol and other volatile compounds using automatic headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography in postmortem specimens. The methodology was initially developed using standard solutions of acetaldehyde, acetone, methanol, and ethanol. Isobutanol was used as internal standard. Postmortem samples of blood, urine, and vitreous humor were obtained during medico-legal autopsies. To date, there are no published paper regarding alcohol analysis in vitreous humor specimens using HS-SPME and limited literature analyzing blood and urine samples. HS-SPME analysis showed that, under optimized conditions, ethanol and isobutanol (internal standard) were well-separated from other volatile compounds such as acetaldehyde, acetone, and methanol considered to be potential interferents in ethanol analysis. The calibration curves for each volatile compound demonstrated good linearity throughout the concentration range from 0.001 to 1.0 g/dl and the detection limit of ethanol in the studied specimens was approximately 0.0001 g/dl.     

气相色谱法测定人血中乙醇的不确定度评估

本文建立了气相色谱法测定人血中乙醇含量的不确定度评定方法,考虑不确定度的来源主要包括仪器的精密度、标准物质标称值的不确定度、样品及标准物质体积的不确定度等。假定传播系数为1,对各分量进行计算与合成。经实验验证,理论推导的结果与实验结果基本吻合。