Chemometrics in analytical chemistry

Chemometrics tools can be used for a wide variety of tasks, including experimental design, exploratory data analysis, and the development of predictive models. In the context of analytical chemistry, however, chemometrics has been shown to be most effective for two general functions  

Instrument specialization Multivariate calibration models are built in order to provide selectivity for a multivariate analytical instrument, or 

Information extraction Chemometrics tools are used to unlock hidden information already present in information-rich multivariate analytical instruments 

Regarding point 1, the need to improve specificity of an analyzer depends on both the analytical technology and the application. For example, chemometrics is required for most NIR spectroscopy applications, because 

Regarding point 2, the information extraction function of chemometrics is a very valnable one that is often overlooked, especially in the industrial world. It will be mentioned later in this chapter that this function can be nsed concurrently with the instrument specialization function, rather than relying npon additional exploratory data analysis. 

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R G Brereton Chemometrics in analytical chemistry, a review, Analyst, 1987, 112, 1635... 

Brereton, RG, Chemometrics in Analytical Chemistry—A Review , Analyst, 112, 635, 1987. 

Adams, MJ. (1995) Chemometrics in Analytical Chemistry, Royal Society of Chemistry, Cambridge. 

To date, the use of chemometrics for method development and robustness testing has been published for all areas of CE, including capillary zone electrophoresis (CZE), capillary electrokinetic chromatography (EKC) using chiral selectors for enantioseparations, micellar electrokinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC). A comprehensive description can be found in Chapters 5 and 13 as well as in recent reviews (6-11). Several monographs on chemometrics in analytical chemistry have been published such as References 12-14. This chapter will... 

Miller, J. N. and Miller, J. C. (2000). Statistics and Chemometrics in Analytical Chemistry, 4th edition, Prentice Hall, Harlow, UK. 

R.G. Brereton, Chemometrics in Analytical Chemistry a Review. Analyst. 112 (1987), 1635-1657. 

The notation chemometrics was introduced in 1972 by the Swede Svante Wold and the American Bruce R. Kowalski. The foundation of the International Chemometrics Society in 1974 led to the first description of this discipline. In the following years, several conference series were organized, for example. Computer Application in Analytics (COMPANA), Computer-Based Analytical Chemistry (COBAC), and Chemometrics in Analytical Chemistry (CAC). Some journals devoted special sections to papers on chemometrics. Later, novel chemometric journals were started, such as the Journal of Chemometrics (WUey) and Chemometrics and Intelligent Laboratory Systems (Elsevier). 

The pioneering works in chemometrics are summarized in some books. In a later phase chemometrics has been presented more fundamentally. Nowadays a series of books for the different aspects of chemometrics are available, such as in analytical chemistry, spectroscopy, calibration, quantitative structure-activity relationships, experimental design, chemical structures, organic synthesis, and neural networks. Research papers in chemometrics are widespread but some concentration occurs in journals of analytical chemistry, chromatography, spectroscopy, and computer chemistry. Two journals have the word chemometrics in their name Chemometrics and Intelligent Laboratory Systems and Journal of Chemometrics. Comprehensive reviews about chemometrics in analytical chemistry have appeared since 1980 every two years 1982, 1984, 1986, 1988, 1990, 1992, 1994, and 1996. ... 

M. Otto, Chemometrics. Statistics and Computer Application in Analytical Chemistry. Wiley-VCH, Weinheim, 1998. 

M. Otto, Chemometrie Statistik und Computereinsatz in der Analytik, WHey-VCH, Weinheim, 1997 M. Otto, Chemometrics. Statistics and Computer Application in Analytical Chemistry, Wiley-VCH, Weinheim, 1998. 

Jurs P C1990. Chemometrics and Multivariate Analysis in Analytical Chemistry. In Lipkowitz K B and D B Boyd (Editors) Reviews in Computational Chemistry Volume 1. New York, VCH Publishers, pp. 169-212. 

A Brief Review of the QSAR Technique. Most of the 2D QSAR methods employ graph theoretic indices to characterize molecular structures, which have been extensively studied by Radic, Kier, and Hall [see 23]. Although these structural indices represent different aspects of the molecular structures, their physicochemical meaning is unclear. The successful applications of these topological indices combined with MLR analysis have been summarized recently. Similarly, the ADAPT system employs topological indices as well as other structural parameters (e.g., steric and quantum mechanical parameters) coupled with MLR method for QSAR analysis [24]. It has been extensively applied to QSAR/QSPR studies in analytical chemistry, toxicity analysis, and other biological activity prediction. On the other hand, parameters derived from various experiments through chemometric methods have also been used in the study of peptide QSAR, where partial least-squares (PLS) analysis has been employed [25]. 

This list of abbreviations contains both acronyms which are generally used in analytical chemistry and such applied in the book. In addition to terms from analytical methods, essential statistical and chemometrical terms as well as acronyms of institutions and organizations are included. Terms of very particular interest are explained on that spot. 

Otto M (1998) Chemometrics. Statistics and computer application in analytical chemistry. VCH, Weinheim... 

Advanced mathematical and statistical techniques used in analytical chemistry are often referred to under the umbrella term of chemometrics. This is a loose definition, and chemometrics are not readily distinguished from the more rudimentary techniques discussed in the earlier parts of this chapter, except in terms of sophistication. The techniques are applied to the development and assessment of analytical methods as well as to the assessment and interpretation of results. Once the province of the mathematician, the computational powers of the personal computer now make such techniques routinely accessible to analysts. Hence, although it would be inappropriate to consider the detail of the methods in a book at this level, it is nevertheless important to introduce some of the salient features to give an indication of their value. Two important applications in analytical chemistry are in method optimization and pattern recognition of results. 

Sample Preparation Techniques in Analytical Chemistry. Edited by Somenath Mitra Analysis and Purification Methods in Combination Chemistry. Edited by Bing Yan Chemometrics From Basics to Wavelet Transform. By Foo-tim Chau, Yi-Zeng Liang, Junbin Gao, and Xue-guang Shao... 

Peter C. Jurs, Chemometrics and Multivariate Analysis in Analytical Chemistry. 

M.J. Adams. Chemometrics in Analytical Spectroscopy (2nd edition). The Royal Society of Chemistry 2004. 

Chemometrics A Textbook published in 1988 by D. L. Massart et al. (1988) was for a long time the Bible (Blue Book) for chemometricians working in analytical chemistry. 

Recently, introductory books about chemometrics have been published by R. G. Brereton, Chemometrics—Data Analysis for the Laboratory and Chemical Plant (Brereton 2006) and Applied Chemometrics for Scientists (Brereton 2007), and by M. Otto, Chemometrics—Statistics and Computer Application in Analytical Chemistry (Otto 2007). Dedicated to quantitative chemical analysis, especially using infrared spectroscopy data, are A User-Friendly Guide to Multivariate Calibration and Classification (Naes et al. 2004), Chemometric Techniques for Quantitative Analysis (Kramer 1998), Chemometrics A Practical Guide (Beebe et al. 1998), and Statistics and Chemometrics for Analytical Chemistry (Miller and Miller 2000). 

With that said process analytical chemistry (PAC) has been commonplace in several industries, even the pharmaceutical industry, prior to 2004. Riebe and Eustace differentiate PAC from analytical chemistry with one word location. PAC is typically spectroscopy, separations or chemometrics, as apphed either at-, in- or on-line to manufacturing. Several comprehensive application reviews of process analytical chemistry have been published in Analytical Chemistry since 1987. " In one of these reviews Workman et al. comment that PAT has continued to evolve as a more appropriate term than PAC while noting PAC has existed since 1911 but is just now finding common usage. The scope of PAT is much broader than that of PAC as the FDA guidance outlines the following desired state for manufacturing ... 

Chemometrics play an important role in analytical chemistry and are involved in both monitoring and control applications. 

By the end of the seventi, Shoenfeld and DeVoe provided the editor of ANALYTICAL CHEMISTRY with the new title Chemometrics for the bi-annual review Statistical and Mathematical Methods in Analytical Chemistry . This was a formal recognition that a new subdiscipline in Analytical Chemistry was born, which was emphasized by the special attention on Chemometrics at a symposium on the occasion of the celebration of ANALYTICAL Chemistry s 50-th anniversary... 

Until now Chemometrics has been considered to be the interface between applied mathematics and analytical chemistry. I believe that by now Chemometrics is also becoming the interface between the analytical chemist and analytical chemistry. This symbiosis of artificial and natural intelligence in analytical chemistry probably can provide an optimal solution In this r pect, I like to quote what Meglen secretary of the Chemometric Society, wrote on the occasion of the tenth anniversary of the Society Chemometrics is clearly beyond infancy. Indeed at ten years old it is remarkably mature . A sign of its maturity the fact that two publishers decided to publish a journal devoted to chemometrics. 

Given the quite simple and clear model of sampling strategies and the economically very important impact of sampling there has been published comparatively little about sampling strategies. The emphasis has been more on analytical techniques. Detection limit, precision and capacity have been the main topics in analytical chemistry for more then 30 years. Chemometrics, providing means to extract more informa-... 

The industrial movement has been bolstered by two decades of advances in materials science, electronics, and chemometrics. Since the inception of CPAC, the pace of innovation in sensors, instrumentation, and analytics has quickened dramatically. The development of more robust, sensitive photodetector materials, microelectromechanical systems (MEMSs), and fiber optics and the perpetual advancement of computing power (as predicted by Moore s law) have both increased the performance and reduced the cost of . As a result, is now a critical part of routine operations within the realm of industrial chemistry. Many general reviews on the subject of (and PAT) have been published [6—10]. A series of literature reviews on the subject of have been published regularly in Analytical Chemistry. 

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