This column has been developed from two recent publications by Tom Fearn. "The effect of spectral pre-treatments on interpretation” and "On the geometry of SNV and MSC"
Tony Davies Columns
A.N. Davies,a H.M. Heiseb and D.F. Ihrigc
aProfessor, SERC, University of Glamorgan, UK, Director, ALIS Ltd, and ALIS GmbH—Analytical Laboratory Informatics Solutions
bISAS—Institute for Analytical Sciences at Dortmund University of Technology, Bunsen-Kirchhoff-Str. 11, D-44139 Dortmund, Germany
cUniversity of Applied Sciences of South-Westphalia, Frauenstuhlweg 31, D-58644 Iserlohn, Germany
This column is about “Computational Chemistry”.
The definition of Chemometrics is: “The application of mathematical and statistical techniques to extract information from complex data”. You might think that it is computational chemistry, but I suspect that the majority of people who use computational chemistry have little knowledge or interest in chemometrics and similarly most chemometricians have little interest in computational chemistry. Computational chemistry uses the results of theoretical chemistry, incorporated into efficient computer programs, to...
I would like to thank everybody who has taken the trouble to respond to my last column on Educating Spectroscopists.1 I am very happy that Ian has allowed me space to reproduce some of them in this edition.
In the previous version of this column, Tony Davies (the younger) was being controversial about education and in this issue, I am being controversial about one of the current applications of chemometrics to the use of spectroscopy in industry.
Now maybe I’m going to be a little controversial in this month’s column and I might just touch a nerve in the readership. If you are of a nervous disposition or are easily upset, this column may damage your health! However, I can’t stop worrying about the miss-match between what we teach undergraduate students about spectroscopy and what they will be expected to understand about our subject when they finally end up in gainful employment.
In our previous column we introduced CVA, one of the very early applications of multivariate analysis (1930s). In this column we will discuss SIMCA (officially it is Soft Independent Modelling of Class Analogies, but no one uses the long form!). SIMCA was invented 30 years later by another pioneer, Svante Wold (the man who coined the word “chemometrics”).
Back in 1999 we looked at the analysis of complex data sets in the field of Ion Mobility Spectrometry (IMS). These were no classical multi-dimensional files such as you would find in time-elapsed spectroscopy or multi-dimensional Nuclear Magnetic Resonance Spectrometry—why?
An Interview with Martin Gerlach discussing the Bayer Technology Services (BTS) Process Analysis approach.
There has been much debate about which program can predict NMR spectra the best. It is well known within the NMR community that spectra prediction strongly depends on the “quality” of the starting data sets for those systems which use real data as a knowledge base. It has become a hot topic in some blogs, although disappointingly most of the authors tend to have affiliations to one software vendor or another.
The starting point for this column is the last one from last year! In that column TD began what was intended to be a two-part story but has, with this column, become a story in four parts. There were required topics we had not covered and we need to begin this column by completing the discussion of removing multiplicative effects by describing what the two most popular methods do to NIR spectra.
When we set up ALIS GmbH one of the first major “discoveries” was probably the most embarrassing for me. Having worked on analytical data standards for so long, I seem to have successfully generated a blind spot for the developments which have taken place in the structure, standardisation and functionality of the Portable Document Format (PDF).2 Maybe it’s due to a subconscious aversion to what I had for a long time seen as a simplistic “get out” solution for those too lazy to convert data into a long-term, stable, vendor-neutral format. How often have we...
The last TD column showed the effect of calculating second derivatives on a set of 100 spectra, which will be the starting point for this column.
This column is about the most basic of pre-treatments, which has been used in spectroscopy well before the word "Chemometrics" was invented.
Tony Davies investigates eMolecules. The system is essentially a clearing-house for metadata and chemical structure metadata indexing of numerous third-party chemical information providers.
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
Norwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK