化学计量学在锕系元素分析中的应用

锕系元素的化学性质相似,各元素的分离和分析都很困难,用传统的数据解析手段,难以实现各元素的同时、快速分析。化学计量学是一种高效、功能强大的数据解析方法,对于样品复杂,基体干扰严重以及多组分样品的分析具有独特优势。将化学计量学应用于锕系元素的分析中,利用数学分离代替化学分离,可直接对样品进行测定。化学计量学方法也可用来指导试样的科学采集,进行实验设计、仪器分析操作条件选择等。从吸收光谱、ICP–AES及放射性测量3个方面综述了化学计量学在锕系元素分析中的应用,阐明了化学计量学在锕系元素分析中的应用难点及发展前景。     

运用色谱指纹图谱与化学计量学方法对灵芝进行分类

采用95%乙醇为提取溶剂,运用高效液相色谱(HPLC)指纹图谱技术与化学计量学方法,对11个不同灵芝菌株子实体进行分类。通过相似度分析分别获得提取样品指纹图谱的13个共有峰及每个样品之间的相似度;以相对共有峰面积为分析参数,运用化学计量学方法包括聚类分析(HCA)、主成分分析(PCA)及判别分析(DA)对其进行分类,结果分为紫芝、赤芝和美国大灵芝3类。实验结果表明,用化学计量学的方法对灵芝样品的指纹图谱数据进行分析,是一种可用于其分类的科学方法。     

信息论与化学计量学

本文讨论了信息论在发展分析化学计量学中的意义和作用以及信息论在化学计量学中应用的一般规律和关系，总结了信息科学对化学计量学发展的贡献。     

基于化学计量学的通用化学数据采集处理系统

研制开发基于化学计量学的通用化学数据采集处理系统，该系统硬件采集部分，可与模拟信号输出的分析仪器或有RS－232接口的分析仪器联接进行数据采集，软件部分的数据处理基于化学计量学理论知识，相应数据处理方法，可从采集到数据中获取大量的信息。软件部分的信息管理包含了大量实验要素的归整、查询和统计等。     

常压电离质谱在公共安全化学毒物检测的应用

常压电离质谱技术(Ambient ionization mass spectrometry,AIMS)以其敞开式环境、简便操作、原位、实时、高通量等优势,成为公共安全化学毒物检测领域的研究热点。该文基于文献计量分析,简要概述了AIMS的分类、发展趋势及其在公共安全化学毒物检测领域的发展现状,重点从检测灵敏度、样品前处理兼容性以及现场检测的小型化质谱适配性等方面,归类总结了AIMS在毒品、爆炸物、化学战剂和生物毒素等分析检测方面的应用特点,最后对其技术特点及未来发展待解决问题等进行了评述,为相关领域研究人员提供有益参考。     

液相色谱和质谱联用技术结合化学计量学应用于代谢组学的研究进展

代谢组学作为系统生物学的重要组成部分,已经成为继基因组学、转录组学、蛋白质组学之后兴起的一个新的组学研究热点。准确全面的检测生物体液中浓度较低的代谢物变化是进行代谢组学研究的基础。液相色谱和质谱联用(LC/MS)技术结合化学计量学很好地实现了对大量样品和微量代谢物的快速定性、定量分析,极大地推动了代谢组学的相关研究。本文综述了LC/MS与化学计量学相结合用于代谢组学研究的现状,并对后续的研究进行了展望。     

化学计量学―光谱法在工农业生产中的应用

化学计量学是近几年发展迅速的化学量测方法。常用的化学计量学方法有小波变换、多元线性回归、偏最小二乘法、主成分分析、人工神经网络、遗传算法等。化学计量学方法与光谱法相结合广泛运用于工业生产、农业生产和环境监测等各个领域,体现出化学计量学在数据处理、信号解析等方面的重要作用。化学计量学―光谱法的建立为工、农业生产中多组分混合物的快速、准确测定及满足质量监控等要求提供了一条有效的途径。     

紫外光谱结合偏最小二乘法用于水样中化学需氧量的测定

结合紫外光谱法和化学计量学方法建立了水样中化学需氧量(COD)的测定方法。采集西宁市湟水河西钢桥至小峡段共42个样品,在190～400 nm波长范围内测定各样品的紫外光谱。用Monte Carlo采样法抽取70%的样本构成训练集,其余样本为独立测试集。分别考察了3种光谱预处理方法和4种特征筛选方法,最终确定COD分析方法为:采用SG-smoothing对光谱平滑后用无信息变量剔除法(UVE)筛选特征波长变量,最后用偏最小二乘法建立多元校正模型。结果在独立测试集上COD的预测误差均方根(RMSEP)为0. 8084,相关系数为0. 9924。紫外光谱法结合化学计量学方法可作为水样中COD测定的一种简洁、有用、快速的方法。     

化学计量学/信息学助推化学与分析测试科学研究范式转换

该文回顾了科学研究范式的形成并讨论了化学与分析测试科学的相关发展历程。实验科学向理论科学演进实际是现代科学的形成过程,对化学而言是一个困难的数学化进程,直到第三即计算科学范式形成,化学的现代科学地位才得以确定。分析化学或分析测试科学发展过程中遇到类似的问题,化学计量学/信息学在助推其完善分析化学“数学化”进程的同时,也能够挖掘更多有效信息。随着现代分析仪器的快速发展和数据海啸的到来,化学计量学/信息学作为成熟的化学学科分支和有力“武器”,正在协助并推动化学和分析测试科学步入第四即“数据密集型”的科学新范式。该文以作者实验室的研究工作为基础,论述了化学计量学/信息学助力推动化学与分析测试科学研究范式的转换过程中的相关进展,并对未来的研究动向进行了展望。     

化学样品混样测试数学模型

建立了适用于化学样品检测的混样测试数学模型。提出以阳性样品检出率作为混样测试的前提条件,结果表明,阳性样品检出率小于30.8%时,可以进行混样测试。结合方法检出限、法规限量确定混样测试的最佳混样数。混样测试数学模型适用于化学样品的定量检测,可提高检测效率,节约检测成本。     

Forensic applications of ambient ionization mass spectrometry

This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques—to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin—are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents.     

Identification and quantification of 34 drugs and toxic compounds in blood,urine, and gastric content using liquid chromatography with tandem mass spectrometry

A liquid chromatography with tandem mass spectrometry method was developed for the simultaneous screening of 34 drugs and poisons in forensic cases. Blood (0.5 mL, diluted 1:1 with water) or 1.0 mL of urine was purified by solid‐phase extraction. Gastric contents (diluted 1:1 with water) were treated with acetonitrile, centrifuged, and supernatant injected. Detection was achieved using a Waters Alliance 2695/Quattro Premier XE liquid chromatography tandem mass spectrometry system equipped with electrospray ionization, operated in the multiple reaction monitoring modes. The method was validated for accuracy, precision, linearity, and recovery. The absolute recovery of drugs and toxic compounds in blood was greater than 51% with the limit of detection in the range of 0.02–20 ng/mL. The absolute recovery of drugs and toxic compounds in urine was greater than 61% with limit of detection in the range of 0.01–10 ng/mL. The matrix effect of drugs and toxic compounds in urine was 65–117% and 67–121% in blood. The limit of detection of drugs and toxic compounds in gastric content samples were in the range of 0.05–20 ng/mL. This method was applied to the routine analysis of drugs and toxic compounds in postmortem blood, urine, and gastric content samples. The method was applied to actual forensic cases with examples given.     

Predictivity of QSAR

A range of good quality, local QSARs for mutagenicity and carcinogenicity have been assessed and challenged for their predictivity in respect to real external test sets (i.e., chemicals never considered by the authors while developing their models). The QSARs for potency (applicable only to toxic chemicals) generated predictions 30-70% correct, whereas the QSARs for discriminating between active and inactive chemicals were 70-100% correct in their external predictions: thus the latter can be used with good reliability for applicative purposes. On the other hand internal, statistical validation methods, which are often assumed to be good diagnostics for predictivity, did not correlate well with the predictivity of the QSARs when challenged in external prediction tests. Nonlocal models for noncongeneric chemicals were considered as well, pointing to the critical role of an adequate definition of the applicability domain.     

Advances in the development and component recognition of latent fingerprints

Fingerprints have been used as an indispensable tool for personal identification in forensic investigations since the late 19 th century. At present, fingerprinting technology has moved away from its forensic roots and is incorporating a broader scientific range, e.g., material science, spectroscopy and spectral analysis, and even in vitro diagnosis. After a brief introduction to latent fingerprints, this mini-review presents the pioneering progresses of fingerprinting technologies including(i) material and electrochemical techniques, and(ii) spectral and spectroscopy imaging techniques and immunological techniques capable of both the visualization of a fingerprint and the detection of chemicals present in it. Finally, perspectives on this rapidly developing field are discussed.     

Selective system of identification and determination of antidepressants and neuroleptics in serum or plasma by solid-phase extraction followed by high-performance liquid chromatography with photodiode-array detection in analytical toxicology.

A selective off-line solid-phase isolation of antidepressants, neuroleptics and other structurally related basic drugs from plasma or serum prior to high-performance liquid chromatography was tested and optimized for general use in toxicological analyses where concomitant drugs can be encountered. The sequential elution preseparated drug mixtures and simplified the subsequent analytical steps. High isolation efficiencies of cyano-bonded silica cartridges from Baker for fifteen amine drugs were determined. Isocratic chromatography on octadecylsilica proved to be very suitable for broad practical applications in complicated cases. The identification of an unknown peak was supported by photodiode-array detection in the range 200-400 nm with a resolution of 2 nm. The linearity of the assay from therapeutic to toxic concentrations was attained. Sufficient sensitivities covering low therapeutic levels of parent drugs and their demethylated metabolites were reached. The system is flexible and allows various methods of quantitative assay to be devised according to the conditions of a particular case in clinical or forensic toxicology.     

Determination of chemical warfare agents and related compounds in environmental samples by solid-phase microextraction with gas chromatography

Solid phase microextraction (SPME) is an increasingly common method of sample isolation and enhancement. SPME is a convenient and simple sample preparation technique for chromatographic analysis and a useful alternative to liquid-liquid extraction and solid phase extraction. SPME is speed and simply method, which has been widely used in environmental analysis because it is a rather safe method when dealing with highly toxic chemicals. A combination of SPME and gas chromatography (GC) permits both the qualitative and quantitative analysis of toxic industrial compounds, pesticides and chemical warfare agents (CWAs), including their degradation products, in air, water and soil samples. This work presents a combination of SPME and GC methods with various types of detectors in the analysis of CWAs and their degradation products in air, water, soil and other matrices. The combination of SPME and GC methods allows for low detection limits depending on the analyte, matrix and detection system. Commercially available fibers have been mainly used to extract CWAs in headspace analysis. However, attempts have been made to introduce new fiber coatings that are characterized by higher selectivities towards different analytes of interest. Environmental decomposition of CWAs leads to the formation of more hydrophilic products. These compounds may be isolated from samples using SPME and analyzed using GC however, they must often be derivatized first to produce good chromatography. In these cases, one must ensure that the SPME method also meets the same needs. Otherwise, it is helpful to use derivatization methods. SPME may also be used with fieldportable mass spectrometry (MS) and GC-MS instruments for chemical defense applications, including field sampling and analysis. SPME fibers can be taken into contaminated areas to directly sample air, headspaces above solutions, soils and water.     

固相微萃取技术在法庭科学领域中的应用

综述国内外固相微萃取技术在法庭科学领域中毒物、毒品和微量物证(炸药残留物、助燃剂残留物、人体气味)样品前处理及分析中的应用,以及在火场助燃剂残留物及人体气味鉴别方面的应用;对固相微萃取技术在法庭科学领域中的发展方向进行了展望。可以对法庭科学领域毒物毒品、微量物的相关研究和侦查办案提供参考。