裂解气相色谱-质谱法分析鉴别轮胎胎面胶

目的对裂解气相色谱-质谱法分析橡胶的裂解条件进行优化,研究利用橡胶特征裂解产物鉴别轮胎胎面胶。方法采用裂解气相色谱-质谱法,确定对NR、BR、SBR的裂解条件及其特征裂解产物,然后根据特征裂解产物及其相对含量并结合聚类分析,对38种轮胎胎面胶进行区分鉴别。结果确定了裂解温度590℃、裂解时间15s及三种橡胶的特征裂解产物;将38个轮胎胎面胶样品的主体成分归为4类,其中NR类5个、SBR类12个、NR/BR并用类5个、NR/SBR并用类16个,且能够对大部分并用类轮胎胎面胶进行鉴别。结论通过优化裂解条件,裂解产物重复性好,特征裂解产物明显,能够确定轮胎胎面胶的主体成分类别并能对大多数并用类轮胎胎面胶样品进行区分鉴别。     

UPLC/Q-TOF-MS 和 PLS-DA 在鸦片生物碱检测及分类判别中的应用

目的建立了鸦片中吗啡、可待因、蒂巴因、罂粟碱、那可汀5种常量生物碱和牛心果碱、劳丹宁、劳丹素等12种痕量生物碱同时分离鉴定的超高效液相色谱-高分辨四极杆飞行时间串联质谱（UPLC/Q-TOF）方法。方法采用Agilent Eclipse Plus C18RRHD（2.1 mm×100 mm,1.8μm）色谱柱,以10 mM甲酸铵溶液和乙腈体系梯度洗脱,使用ESI离子源,正离子模式下采集数据。结果借助UPLC的快速分离和Q-TOF-MS测定的精确分子量和二级碎片信息,实现了17种生物碱的检测。应用SIMCA-P软件对78份国产鸦片和200份缅甸产鸦片进行偏最小二乘法判别分析（partial least squaresdiscriminate analysis,PLS-DA）,比较不同地区鸦片样品中生物碱的差异,建立了区分国产鸦片和缅甸产鸦片的判别方法。结论所建立的方法用于鸦片样品中常量和痕量生物碱的检测及鸦片样品的产地判别,具有快速、高效、灵敏、准确的特点。     

Saliva identification in forensic samples by automated microextraction and intact mass analysis of statherin

The enzyme α-amylase has long been a commonly targeted protein in serological tests for saliva. While being especially abundant in saliva, α-amylase is detectable in vaginal secretions, sweat, fecal matter, breast milk and other matrices. As a result, assays for α-amylase only provide a presumptive indication of saliva. The availability of mass spectrometry-based tools for the detection of less abundant, but more specific, protein targets (e.g., human statherin) has enabled the development of high confidence assays for human saliva. Sample throughput, however, has traditionally been low due to multi-step workflows for protein extraction, quantitation, enzymatic digestion, solid phase cleanup, and nano-/capillary-based chromatography. Here, we present two novel “direct” single-stage extraction strategies for sample preparation. These feature immunoaffinity purification and reversed-phase solid-phase microextraction in conjunction with intact mass analysis of human statherin for saliva identification. Mass analysis was performed on the Thermo Scientific Q-Exactive™ Orbitrap mass spectrometer with a 10-min analytical run time. Data analysis was performed using Byos^® from Protein Metrics. Two sample sets were analyzed with a population of 20 individuals to evaluate detection reliability. A series of casework-type samples were then assayed to evaluate performance in an authentic forensic context. Statherin was confidently identified in 92% and 71% of samples extracted using the immunoaffinity purification and solid phase microextraction approaches, respectively. Overall, immunoaffinity purification outperformed the solid phase microextraction, especially with complex mixtures. In toto, robotic extraction and intact mass spectrometry enable the reliable identification of trace human saliva in a variety of sample types.     

Quantification of psilocin in human whole blood using liquid chromatography–tandem mass spectrometry (LC–MS/MS)

There has been burgeoning interest in psilocybin-use for the treatment of various neurological and neurodegenerative diseases. Psilocybin is mistakenly perceived as the principal pharmacologically active compound due to its high concentrations found in magic mushrooms; however, it is the prodrug of psilocin. Despite the expanding body of clinical research seeking to understand the pharmacodynamic/pharmacokinetic properties of psilocin, and its role in inducing dramatic changes to cognitive function, there has not been a corresponding increase in the development of sensitive analytical methods that can quantify psilocin in different biological fluids. Existing analytical methods have been developed using plasma, serum, and urine as the matrix of choice, but with the unknown blood-to-plasma ratio of psilocin, any pharmacokinetic conclusions drawn solely on plasma data may be misleading. Thus, the main objective of this study is to develop the first analytical method that utilizes SPE and LC–MS/MS to quantify psilocin in human whole blood. The SPE procedure yielded a high recovery efficiency (≥89%) with minimal matrix effects. The method was validated according to ANSI/ASB 036 guidelines. Linearity was between 0.7–200 ng/mL and encompassed previously reported ranges found in plasma/serum. Bias, within- and between-run precision for all quality controls met ANSI/ASB 036 acceptability criteria. Endogenous/exogenous interferences and carryover were negligible. Psilocin stability was assessed at 4°C over 48 h and was considered stable. Although a proof-of-concept study will need to be performed to characterize the method, this analytical workflow was able to detect and quantify psilocin in human whole blood at low limits of quantification.     

Designer Psychostimulants in Urine by Liquid Chromatography–Tandem Mass Spectrometry,

Designer psychostimulants are known by recreational drug users to produce a complex array of adrenergic and hallucinogenic effects. Many of these drugs are not targeted during routine toxicology testing and as a consequence, they are rarely reported. The purpose of this study was to develop a procedure for the detection of 15 psychostimulants in urine using liquid chromatography–tandem mass spectrometry (LC‐MS/MS), specifically 2,5‐dimethoxy‐4‐bromophenethylamine (2C‐B), 2,5‐dimethoxy‐4‐chlorophenethylamine (2C‐C), 2,5‐dimethoxy‐4‐methylphenethylamine (2C‐D), 2,5‐dimethoxy‐4‐ethylphenethylamine (2C‐E), 2,5‐dimethoxyphenethylamine (2C‐H), 2,5‐dimethoxy‐4‐iodophenethylamine (2C‐I), 2,5‐dimethoxy‐4‐ethylthiophenethylamine (2C‐T‐2), 2,5‐dimethoxy‐4‐isopropylthiophenethylamine (2C‐T‐4), 2,5‐dimethoxy‐4‐propylthiophenethylamine (2C‐T‐7), 2,5‐dimethoxy‐4‐bromoamphetamine (DOB), 2,5‐dimethoxy‐4‐chloroamphetamine (DOC), 2,5‐dimethoxy‐4‐ethylamphetamine (DOET), 2,5‐dimethoxy‐4‐iodoamphetamine (DOI), 2,5‐dimethoxy‐4‐methylamphetamine (DOM), and 4‐methylthioamphetamine (4‐MTA). Analytical recoveries using solid‐phase extraction were 64–92% and the limit of detection was 0.5 ng/mL for all drugs except 2C‐B (1 ng/mL). The assay was evaluated in terms of analytical recovery, precision, accuracy, linearity, matrix effect, and interferences. The technique allows for the simultaneous detection of 15 psychostimulants at sub‐ng/mL concentrations.     

Optimization of Headspace Solid‐Phase Microextraction Technique for Extraction of Volatile Smokeless Powder Compounds in Forensic Applications

Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid‐phase microextraction technique using an 85 μm polyacrylate fiber followed by gas chromatography‐flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction‐influencing parameters. A 2⁴ factorial first‐order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders.     

缅甸油气产业开发现状与外国参与情况评析

缅甸油气领域正处于开发活跃期,但油气产量不均衡,油少气多。西方发达国家企业曾长期是缅甸油气开发的先锋和主力,然而,本世纪以来,东盟及缅甸周边国家石油企业跃升为缅甸油气开发的新主力军。2010年缅甸开启民主进程,西方企业投资缅甸油气领域将出现恢复性增长,但难以改变现有的外资参与结构。     

串联质谱技术在物证鉴定中的应用

串联质谱是近年来发展迅速且能提供丰富信息的质谱新技术。本文综述了串联质谱的基本原理、操作模式、仪器类型以及该技术在物证鉴定中的应用。     

固相微萃取（SPME）GC／MS、GC／MS／MS法检测环境水中的有机磷杀虫剂

目的　通过对固相微萃取 (SPME)条件的优化、筛选实验 ,建立环境水中有机磷杀虫剂的快速检验方法。方法　收集 17种有机磷杀虫剂 ,使用SPME并结合GC/MS、GC/MS/MS检验方法。结果　该方法简便、灵敏、迅速、可靠 ,样品利用率高 ,最低检测浓度为 0 .0 1～ 10 0 pg/ml,在痕量范围 0 .1～ 10ng/ml内线性回归好(相关系数r达 0 .99以上 )。结论　实际应用效果理想 ,有望成为公安、环保、检验检疫的农残及毒物分析中的一种快速有效的分析方法。     

SPME与GC/MS相结合检验尿液中的氯胺酮

目的应用固相微萃取与气相色谱-质谱联用技术分析尿液中的氯胺酮。方法对影响SPME萃取效果的萃取头类型、萃取时间、解析时间、离子强度等因素条件进行优化,分析尿中氯胺酮。结果在0.5~2.5μg/m l范围内线性关系良好,线性相关系数为0.995 6;最小检出限为2.5μg/L。结论该方法具有预处理简单、分析速度快、灵敏度高等优点,适合实际案件尿样的检验。