Analytical chemical methods as systems producing chemical information by inference

Summary Analytical chemical methods as systems produce chemical information about the material to be analyzed. Analytical chemical systems as semiosis consist of analytical signal production and analytical chemical signal interpretation and produce chemical information by inference in an indirect way through analytical information. From the logical point of view the chemical information produced by analytical chemical systems is only credible. Generalizing the results the idea of diagnostic systems can be introduced and the analytical chemical methods as systems are a special type of diagnostic systems.

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Chemisch-analytische Systeme zur Erlangung chemischer Informationen

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Presented at the First International Symposium on History and Philosophy in Analytical Chemistry, Vienna, November 22–23, 1985     

Interpretation of analytical chemical information by pattern recognition methods-a survey

Since the late sixties, pattern recognition techniques have been used by analytical chemists to facilitate the interpretation of multivariate analytical information. Most research within the field has focused on adapting pattern recognition methods to chemical data. This has been necessary since chemical data are often complicated by the fact that distributions are unknown. Through the first decade of chemical pattern recognition, promising results have been obtained even though the data sets studied have frequently been rather small for statistical analysis. The past few years have shown that an increasing number of analytical chemists are interested in the sheer utility of pattern recognition. This can be taken as a valid sign of a useful approach. The present communication surveys this development. Those methods which have proved most useful for analytical chemical data are described in some detail, and applications within the various fields of analytical chemistry are reviewed.     

Informationsgewinn bei analytisch-chemischen Messungen

Summary The aim of every analytical experiment is to gain information about a particular chemical system. In order to design and carry out such an experiment it is necessary to take into consideration the chemical properties of the matter as well as the metrological rules inherent in the analytical method applied. In this aim (to obtain information) and in the manner of working (to regard chemical properties and metrological rules) analytical chemistry can be seen as being a uniform and independent scientific discipline. The different analytical methods and the numerous analytical problems can then be described in uniform manner. The different measuring parameters and steps in analytical work can all be reduced to uniform terms and processes. The treatment and evaluation of the signal produced in the analytical experiment is always at the centre of all discussions. The uniform theoretical interpretation of seemingly different methodological terms makes a standardized nomenclature possible. The aim of effectively obtained information explains the preference of certain analytical methods for trace analysis, structure analysis, multicomponent analysis or other analytical problems. Furthermore, it is possible to derive useful strategies for applying an analytical method or managing an analytical problem. Finally, tendencies can be shown for the development of analytical methods, which are particularly effective in obtaining information.     

Elastomers: sulphur or peroxide cross‐linked? An analytical approach

The analytical methods presented in this study lead to a characterisation of the vulcanisation system of unknown elastomers. The chemical determination of sulphur gives a first impression of the system. However, it cannot be proved with any degree of certainty weather a product is sulphur cross‐linked or not. Other wet chemical methods (colour reactions) are more suitable for quality control of already known systems. Most spectrometric methods (infrared spectrometry, Raman spectrometry, nuclear resonance spectrometry) are only of use for special applications and for research. A more precise characterisation is obtained by means of chromatographic methods , i.e. by identifying the products, which originated from thermal degradation of the cross‐linking reagents (sulphur, sulphur donators, peroxides). Evolved‐Gas‐Analysis (EGA) and pyrolysis gas chromatography with adequate detectors proved to be very successful as chemical‐analytical methods for such investigations. In order to make a reliable statement about the vulcanisation system of unknown elastomeric material, the results of several analytical methods have to be collected and evaluated.     

分析化学的“昨天、今天和明天”

简述了分析化学的发展历史。分析化学的"昨天",从基于物理化学的溶液理论,以目视可见为工具的"化学分析",进入以物理方法为基础的仪器分析,因此有人提出"化学正在走出分析化学";分析化学的"今天",因为它的主体任务是解决物质的分子原子结构和成分,所以又回归化学领域;对分析化学的"明天"寄厚望,分析化学走出历来仅仅以"为他人报告提供数据"的技术支持者的角色,成为"实际问题解决者",利用分析化学中综合分析的"剖析技术",为新产品开发创制的"反工艺研究"做出独特的贡献。     

氰化物分析研究进展

介绍氰化物常用的场外分析和现场检测方法,对实验室(场外)常用分析方法如化学滴定法、分光光度法、色谱法、波谱法等以及现场快速检测方法如目视比色法、分光光度计法等进行了综述,并结合实际需求,总结了不同方法的特点,展望了氰化物检测方法的未来发展趋势。     

Cross validation of multiple methods for measuring pyrethroid and pyrethrum insecticide metabolites in human urine

The objective of our study was to compare three vastly different analytical methods for measuring urinary metabolites of pyrethroid and pyrethrum insecticides to determine whether they could produce comparable data and to determine if similar analytical characteristics of the methods could be obtained by a secondary laboratory. This study was conducted as a part of a series of validation studies undertaken by the German Research Foundation’s Committee on the Standardization of Analytical Methods for Occupational and Environmental Medicine. We compared methods using different sample preparation methods (liquid–liquid extraction and solid-phase extraction with and without chemical derivatization) and different analytical detection methods (gas chromatography–mass spectrometry (single quadrupole), gas chromatography–high resolution mass spectrometry (magnetic sector) in both electron impact ionization and negative chemical ionization modes, and high-performance liquid chromatography–tandem mass spectrometry (triple quadrupole) with electrospray ionization). Our cross validation proved that similar analytical characteristics could be obtained with any combination of sample preparation/analytical detection method and that all methods produced comparable analytical results on unknown urine samples. Cross-method comparison using unknown urine samples revealed reasonably good agreement for any combination of the methods tested     

醛类标志物的化学衍生化色谱-质谱分析方法进展

人体接触环境中的化学污染物会导致多种疾病,包括癌症、糖尿病、心血管疾病、神经退行性疾病(阿尔茨海默症、帕金森病等)等。作为一类具有高反应活性的亲电化合物,醛类(包括外源性醛类或环境污染物暴露后产生的内源性醛类)可与人体中多种重要生物分子形成共价修饰产物而产生毒害作用。暴露组研究自2005年被首次提出以来一直是一个前沿热门领域,暴露组研究可绘制生物标志物与疾病风险之间的复杂关系,因此,所有生物标志物的可测量的和特征性的变化共同构成了暴露组研究的关键基础。醛类是化学暴露组的主要成分之一。由于醛类化合物自身物理化学性质和样品大量基质干扰存在,对它们进行分析和表征特别困难。醛类化合物的分析检测方法主要有传感分析法、电化学法、荧光成像、色谱法、质谱法、色谱-质谱联用法等。基于色谱-质谱的分析技术已成为化学暴露组研究的主要方法之一。化学衍生化,特别是稳定同位素标记衍生化(亦称化学同位素标记)结合液相色谱-质谱(LC-MS)技术能够解决靶向和非靶向代谢组和暴露组分析工作中的诸多问题。化学衍生化联合色谱-质谱的分析策略是复杂体系中醛类精准分析非常重要的解决方案之一。特别是近5年,基于化学衍生化的色谱-质谱分析方法开发与应用已成为醛类分析方法中的热点和亮点。该文主要总结与评述了近5年基于化学衍生化的气相色谱-质谱(GC-MS)和LC-MS最新进展,重点关注生物基质(血液、尿液、唾液、生物组织等)中醛类暴露标志物的分析方法进展。通过探讨标记小分子醛的各种衍生试剂、定性/定量分析方法及应用价值,评述醛类暴露标志物不同分析方法的优缺点以及未来发展趋势,为暴露组学、代谢组学、脂质组学的整合发展和环境生态健康研究提供一定的帮助。为了阐明外源性和内源性醛类化合物在生理和病理事件中所起的复杂作用,需要大力改进研究醛组学(aldehydome)的分析表征技术和工具。随着更先进的质谱仪的研发和使用,以及高效色谱分离和不断进步的生物信息学手段,并同时伴随着单细胞分析、质谱成像的兴起,未来的醛类暴露组分析方法会具有更高的灵敏度、更高的分析通量,更有希望筛选鉴定未知醛类化合物并发现新的暴露组生物标志物。     

化学测量过程中信息流的传递

结合分析化学课程学习与文献研究心得,对化学测量过程中信息流传递及其包含的哲学思想进行简要的讨论,旨在帮助本科学生在学习分析化学课程时能发现各种分析方法之间的本质联系,以对分析化学知识体系有较为系统的理解与掌握。     

The current state of analytical control in Lithuania

In Lithuania research and development in chemical analysis are concentrated in scientific institutes and universities. The main fields of interest focus on biosensors, electrochemical sensors, sampling techniques and methods, study of atomization processes in spectrochemical analysis and noise evaluation in analytical measurements. Some laboratories also take part in international environmental monitoring programmes. There are about 50 researchers at the Ph.D. level engaged in analytical chemistry and several hundred technicians specialized in the field of analytical control. About one hundred chemical laboratories are active in scientific institutes, universities and factories. Specialized laboratories of chemical analysis are at the disposal of Environmental Control and Health Protection Departments and forensic investigation organizations. So far no laboratories are accredited according to the ISO 9000 norms. Special courses on analytical chemistry are offered at a few schools of higher education in the country. Only at the Department of Analytical Chemistry of the University of Vilnius specialized programmes are available to postgraduate students working towards a Ph.D. to improve their skills in current techniques of analytical chemistry. Recently the Technical Committee TC-16 for Chemical Analysis was formed within the standardization system of Lithuania. Its main activities are centered on issues such as national terminology, certified reference materials (CRMs), analytical methods and analytical quality assurance. There are numerous problems related to national terminology, the preparation of special documents in the field of analytical control and the production of regional environmental CRMs. Problems, also arise in obtaining and using CRMs for analytical instrument calibration and validation.