Articles
A.M.C. Davies
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK. [email protected]
N.M. Faber,a,* and R. Rajkób
aChemometric Consultant, Rubensstraat 7, 6717 VD Ede, The Netherlands. [email protected]
bDepartment of Unit Operations and Food Engineering, Szeged College of Food Engineering, University of Szeged, H-6701 Szeged, POB 433, Hungary
A.M.C. Davies
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
Tony Davies,a John Trygg,b Pavel Matĕjkac and KarolVolka
aExternal Professor, University of Glamorgan, UK, Director, ALIS Ltd, Analytical Laboratory Informatics Solutions
bPhaseFour Informatics Limited, [email protected]
cDepartment of Analytical Chemistry, Institute of Chemical Technology, Technika 5, 166 28 Prague 6–Dejvice, The Czech Republic
A.M.C. Daviesa and Tom Fearnb
aNorwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
bDepartment of Statistical Science, University College London, Gower Street, London, UK
Tony Davies,a Wolfgang Robienb and Jeff Seymourc
aExternal Professor, University of Glamorgan, UK, Director, ALIS Ltd, Analytical Laboratory Informatics Solutions
bInstitute for Organic Chemistry, University of Vienna, Austria
cModgraph Consultants, 1 Oakland View, Welwyn AL6 0RJ, UK
A.M.C. Daviesa and Tom Fearnb
aNorwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
bDepartment of Statistical Science, University College London, Gower Street, London, UK
Tony N. Davies,a Robert J. Lancasterb and Peter Lampenc
aExternal Professor, University of Glamorgan, UK
c/o Waters Informatics, Europaallee 27–29, 50226 Frechen, Germany
bUniversity of West Indies, Mona Campus, Jamaica
cISAS, Institute for Analytical Science, Bunsen-Kirchoff-Strasse 11, 44139 Dortmund, Germany
A.M.C. Daviesa and Tom Fearnb
aNorwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
bDepartment of Statistical Science, University College London, Gower Street, London, UK
Tony Davies
External Professor, University of Glamorgan, UK
c/o Waters Informatics, Europaallee 27–29, 50226 Frechen, Germany
A.M.C. Davies
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
Introduction
In my last column I began a revision of basic chemometrics.1 In this column I will discuss some interpretation of the results produced by principal component analysis (PCA) as part two of this revision programme.
Tony Davies
External Professor, University of Glamorgan, UK, c/o Waters Informatics, Europaallee 27–29, 50226 Frechen, Germany
PCA is a mathematical method of reorganising information in a data set of samples. It can be used when the set contains information from only a few variables but it becomes more useful when there are large numbers of variables, as in spectroscopic data.
Peter Lampena and Tony Daviesb
aISAS, Institute for Analytical Sciences, Bunsen-Kirchhoff-Str.11, 44139 Dortmund, Germany
bExternal Professor, University of Glamorgan, UK. c/o Waters Informatics, Europaallee 27–29, 50226 Frechen, Germany
A.M.C. Davies
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
Tony Davies
External Professor, University of Glamorgan, UK c/o Waters Informatics, Europaallee 27–29, 50226 Frechen, Germany
The goal of building a multivariate calibration model is to predict a chemical or physical property from a set of predictor variables, e.g. analyte concentration or octane number from a near infrared (NIR) spectrum. A good multivariate calibration model should be able to replace the laborious, possibly imprecise reference method. The quality of a model therefore primarily depends on its predictive ability. Other properties such as interpretability of the model coefficients might also be of interest, but here the focus is on the problem of quantifying the predictive ability.
Tony Davies
External Professor, University of Glamorgan, UK, c/o Creon Lab Control AG, Europaallee 27–29 50226 Frechen, Germany
A.M.C. Davies
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK
Tony Davies,a Peter Lampen,b Maren Fiege,c Thorsten Richterc and Thorsten Fröhlichc
aExternal Professor, University of Glamorgan, UK. c/o Creon Lab Control AG, Europaallee 27-29 50226 Frechen, Germany
bISAS, institute for Spectrochemistry and Applied Spectroscopy, Dortmund, Germany
cCreon Lab Control AG, Europaallee 27-29 50226 Frechen, Germany
