Chemical chemometrics, definition

A definition of Chemometrics is a little trickier of come by. The term was originally coined by Kowalski, but nowadays many Chemometricians use the definition by Massart [4], On the other hand, one compilation presents nine different definitions for Chemometrics [5, 6] (including What Chemometricians do , a definition that apparently was suggested only HALF humorously ). But our goal here is not to get into the argument over the definition of the term, so for our current purposes, it is convenient to consider a perhaps somewhat simplified definition of Chemometrics as meaning multivariate methods of data analysis applied to data of chemical interest . 

Despite the broad definition of chemometrics, the most important part of it is the application of multivariate data analysis to chemistry-relevant data. Chemistry deals with compounds, their properties, and their transformations into other compounds. Major tasks of chemists are the analysis of complex mixtures, the synthesis of compounds with desired properties, and the construction and operation of chemical technological plants. However, chemical/physical systems of practical interest are often very complicated and cannot be described sufficiently by theory. Actually, a typical chemometrics approach is not based on first principles—that means scientific laws and mles of nature—but is data driven. Multivariate statistical data analysis is a powerful tool for analyzing and structuring data sets that have been obtained from such systems, and for making empirical mathematical models that are for instance capable to predict the values of important properties not directly measurable (Figure 1.1). 

With this in mind, I ask the reader to accept my humble definition of chemometrics the application of multivariate, empirical modeling methods to chemical data [2]. 

Before describing the six habits, it is important to define what is meant by the term chemometrics. A general definition is the use of statistical and mathematical techniques to analyze chemical data. In this book, we prefer the broader definition of chemometrics as the entire process whereby data (e.g., numbers in a table) are transformed into information used for decision making. ... 

In 1997, D.L. Massart suggested the following definition "Chemometrics is a chemical discipline that uses mathematics, statistics and formal logic (a) to design or select optimal experimental procedures (b) to provide maximum relevant chemical information by analyzing chemical data and (c) to obtain knowledge about chemical systems" (Massart et ah, 1997). 

As the definition says, a model is a description of a real phenomenon performed by means of mathematical relationships (Box and Draper, 1987). It follows that a model is not the reality itself it is just a simplified representation of reality. Chemometric models, different from the models developed within other chemical disciplines (such as theoretical chemistry and, more generally, physical chemistry), are characterized by an elevated simplicity grade and, for this reason, their validity is often limited to restricted ranges of the whole experimental domain. 

Key words in the definition are optimal and material systems . These express the fact that chemical analysis is related to a problem and not to a sample and that economical aspects of chemical analysis prevail. The result of chemometric research is chemometric software, which enable a large scale implementation and application of chemometric tools in practical chemical analysis. 

Over the last 30 years, chemometrics has evolved into an interdisciplinary subdiscipline of chemistry that combines mathematical modeling, multivariate statistics, and chemical measurements. There have been numerous definitions of the... 

First of all, what is Chemometrics According to the definition of the Chemometrics Society, it is the chemical discipline that uses mathematical and statistical methods to design or select optimal procedures and experiments, and to provide maximum chemical information by analyzing chemical data. ... 

In the field of electrochemical sensors for liquids, there is the recent approach known as electronic tongue, which is inspired on the sense of taste. A widely accepted definition of electronic tongue (Holmberg et al. 2004) entails an analytical instrument comprising an array of non-specific, poorly selective, chemical sensors with crosssensitivity to different compounds in a solution, and an appropriate chemometric tool for data processing. 

Chemometrics is the science of relating measurements made on a chemical system (including dynamic chemical processes) to the state of the system via application of mathematical or statistical algorithms. It is clear from this definition that chemometrics is data based. The goal of many chemometric techniques is the production of an empirical model, derived from data, that allows one to estimate one or more properties of a system from measurements. The four important performance attributes that can be improved through the use of chemometric techniques are accuracy, precision, robustness, and reproducibility. 

NIR analysts often use a statistical methodology called chemometrics to calibrate an NIR analysis. Chemometrics is a specialized branch of mathematical analysis that uses statistical algorithms to predict the identity and concentration of materials. Chemometrics is heavily used in NIR spectral analysis to provide quantitative and qualitative information about a variety of pure substances and mixtures. NIR spectra are often the result of complex, convoluted, and even unknown interactions of the different molecules and their environment. As a result, it is difficult to pick out a spectral peak or set of peaks that behave linearly with concentration or are definitive identifiable markers of particular chemical structures. Chemometrics uses statistical algorithms to pick out complex relationships between a set of spectra and the material s composition and then uses the relationship to predict the composition of new materials. Essentially, the NIR system, computer, and associated software are trained to relate spectral variation to identity and then apply that training to new examples of the material. 

Using a widely accepted definition, chemometrics can be understood as the chemical discipline that uses mathematical, statistical, and other meth-... 

Chemometrics is often defined as the application of statistics and mathematics to the analysis of chemical data. Without arguing the sufficiency of this definition, it is safe to say that the application of multivariate statistical and mathematical spectral analysis methods to near-infrared (NIR) data provides an intriguing set of advantages absent in univariate analysis of NIR data. Foremost of these advantages are the abilities to preprocess NIR spectra for removal of complex background signals, perform multianalyte calibration and calibration in the presence of multiple changing chemical... 

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