Analytical science definition

J. Incedy, T. Lengyel and A.M. Ure, IV PAC Compendium of Analytical Nomenclature Definitive Rules 1997, Blackwell Science, Oxford, 3rd edn., 1998. 

This Handbook aims to explain terminology widely used, and sometimes misused, in analytical chemistry. It provides much more information than the definition of each term but it does not explain how to make measurements. Additionally, it does not attempt to provide comprehensive coverage of all terms concerned with chemistry, instrumentation or analytical science. The authors have addressed primarily those terms associated with the quality assurance, validation and reliability of analytical measurements. The Handbook attempts to place each term in context and put over concepts in a way which is useful to analysts in the laboratory, to students and their teachers, and to authors of scientific papers or books. This approach is particularly important because official definitions produced by many international committees and organisations responsible for developing standards are frequently confusing. In a few cases the wording of these definitions completely obscures their meaning from anyone not already familiar with the terms. 

Compendium of Analytical Nomenclature Definitive Rules. 1997. International Union of Pure and Applied Chemistry, prepared by J. Inczedy, T. Lengyel. and A. M. Ure, pp. 2-8. Malden. MA Blackwell Science, 1998. 

IUPAC Compendium of Analytical Nomenclature, Definitive Rules, 3rd Edition, Blackwell Science (1997). 

Many attempts have been made to provide a satisfactory definition of analytical science. The most recent is that proposed by the Working Party on Analytical Chemistry of the Federation of European Chemical Societies Analytical Chemistry (1994) 66 98A-101A) it reads ... 

The specialized terminology of Analytical Chemistry has been the enduring responsibility of the Analytical Division of lUPAC. The terminology is to be found in the Compendium of Analytical Nomenclature. Definitive Rules 1997 (1998), 3rd edn., Oxford Blackwell Scientific Publications, prepared for publication by Inczedy J, Lengyel T, and Ure AM (the so-called Orange Book). Nomenclature, of course, reflects the relentless advance of science, so new and revised definitions are continually being published, initially for consultation by the international community, in Pure and Applied Chemistry. 

As with many concepts in the analytical sciences, the concept of LOD suffers from the curse of intuition. That is to say that although the concept is, on an intuitive leveL clear to all practitioners of the analytical sciences, if one were to ask the practitioners to define the term and describe its determination, one would end up with nearly as many definitions and determination methods as there are practitioners. This is borne out in the scientific literature, which contains literally hundreds of references with the more or less general content of my (our) definition of the LOD and how I (we) recommend you determine it (e.g.. Table 2). It is borne out by the fact that although several organizations have attempted to unify, or harmonize, the individual definitions, their own results, in fact, are not the same. 

International Union of Pure and Applied Chemistry (1998) Compendium of Analytical Nomenclature, Definite rules 1997. Oxford Blackwell Science. 

FIGURE 10.4 Schematic diagram of the response function of an ion-selective electrode, denotes the activity of the primary ion, i and region I the activity range where the cell potential is independent of the primary ion activity. (Taken from Inczedy, J. et al.. Compendium of Analytical Nomenclature Definitive Rules 1997, 3rd ed., Blackwell Science, Oxford, U.K., 1998, p. 288. With permission.)... 

The first definition that is focused directly on the role of analytical signals was given by Pungor who characterizes analytical chemistry as a science of signal production and interpretation (Veress et al. [1987], Lewenstam and Zytkow [1987]). Zolotov [1984] characterized chemical, physicochemical and physical methods of analytical chemistry as follows All of them, however, have the same feature it is the dependence of signal on analyte... 

To overcome the unsatisfactory situation in the understanding the meaning of analytical chemistry at the end of the last century, an international competition was organized in 1992 by noted European analytical chemists and the Fresenius Journal of Analytical Chemistry to characterize analytical chemistry as an autonomous field of science by a topical and proper definition. The title of this competition was Analytical Chemistry - today s definition and interpretation and 11 out of 21 contributions were published in Fresenius J Anal Chem (Fresenius and Malissa [1992] Cammann [1992] Valcarcel [1992] Zuckerman [1992] Zhou Nan [1992] Koch [1992] Perez-Bustamante [1992] Ortner [1992] Danzer [1992] Green [1992] Stulik and Zyka [1992] Kuznetsov [1992]). 

All these definitions express essential aspects of analytical chemistry and the analytical work. Some others - with originality - could be added, such as that from Murray [1991] who characterized analytical chemistry briefly and aptly as the science of chemical measurements . 

Lisa Lloyd I disagree with what Professor Williams just said. I think that every time you use the word reductionist , I would have used analysis . I think that it is correct that scientists use analysis to break systems down, but I think of reductionism as being something else which is the complete description of entire systems in terms of entities at a lower level. That s the sort of standard philosophical definition of reductionism which has a lot more metaphysical and epistemological bite than does the kind of analytic method that you are describing. So I would want to distinguish between analysis as a method, a set of approaches that all scientists do use, and reductionism as a set of commitments about what the ultimate aims of science or of a scientific theory would be, which is explanation at the lowest possible level. Does that make sense to you ... 

The chemical world is often divided into measurers and makers of molecules. This division has deep historic roots, but it artificially impedes taking advantage of both aspects of the chemical sciences. Of key importance to all forms of chemistry are instruments and techniques that allow examination, in space and in time, of the composition and characterization of a chemical system under study. To achieve this end in a practical manner, these instruments will need to multiplex several analytical methods. They will need to meet one or more of the requirements for characterization of the products of combinatorial chemical synthesis, correlation of molecular structure with dynamic processes, high-resolution definition of three-dimensional structures and the dynamics of then-formation, and remote detection and telemetry. 

As the analytical, synthetic, and physical characterization techniques of the chemical sciences have advanced, the scale of material control moves to smaller sizes. Nanoscience is the examination of objects—particles, liquid droplets, crystals, fibers—with sizes that are larger than molecules but smaller than structures commonly prepared by photolithographic microfabrication. The definition of nanomaterials is neither sharp nor easy, nor need it be. Single molecules can be considered components of nanosystems (and are considered as such in fields such as molecular electronics and molecular motors). So can objects that have dimensions of >100 nm, even though such objects can be fabricated—albeit with substantial technical difficulty—by photolithography. We will define (somewhat arbitrarily) nanoscience as the study of the preparation, characterization, and use of substances having dimensions in the range of 1 to 100 nm. Many types of chemical systems, such as self-assembled monolayers (with only one dimension small) or carbon nanotubes (buckytubes) (with two dimensions small), are considered nanosystems. 

Thus, as often occurs in petroleum science (Speight, 1999), the definition of total petroleum hydrocarbons depends on the analytical method used because the total petroleum hydrocarbons measurement is the total concentration of the hydrocarbons extracted and measured by a particular method. The same sample analyzed by different methods may produce different values. For this reason, it is important to know exactly how each determination is made since interpretation of the results depends on understanding the capabilities and limitations of the method. If used indiscriminately, measurement of the total petroleum hydrocarbons in a sample can be misleading, leading to an inaccurate assessment of risk. 

A broadly accepted definition of process analytics is difficult to capture as the scope of the methodology has increased significantly over the course of its development. What was once a subcategory of analytical chemistry or measurement science has developed into a much broader system for process understanding and control. Historically, a general definition of process analytics could have been ... 

There are many reasons for the need to validate analytical procedures. Among them are regulatory requirements, good science, and quality control requirements. The Code of Federal Regulations (CFR) 311.165c explicitly states that the accuracy, sensitivity, specificity, and reproducibility of test methods employed by the firm shall be established and documented. Of course, as scientists, we would want to apply good science to demonstrate that the analytical method used had demonstrated accuracy, sensitivity, specificity, and reproducibility. Finally management of the quality control unit would definitely want to ensure that the analytical methods that the department uses to release its products are properly validated for its intended use so the product will be safe for human use. 

In analytical and in environmental sciences there is a constant challenge to enhance instrumental performance and to detect lower and lower trace amounts. It seems also to be a challenge for statistical refinement of the definition of the limits briefly considered above. Until now the soundest approach to this field is probably that given by LUT-HARDT et al. [1987]. The reader who is not forced to follow statutory regulations (DIN, ISO, BS,...) may try his own literature search. 

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