Tony (A.M.C.) continues down the last furlong of his series of Tony Davies Column articles. This issue, he considers principal component analysis (PCA). Using research recently published in the Journal of Near Infrared Spectroscopy, he explains that PCA is a very useful tool but it will not solve all our problems. Two old articles on PCA, including Tony’s concept of the “Data Cake” have been added to the website, are referenced in Tony’s article and can be freely downloaded by readers.
Tony Davies Columns
Robert Lancashire reports from the Chemical Information Division (CINF) of the American Chemical Society meeting at their recent 246th ACS National Meeting and Exposition.
Now that Tony understands wavelets, he is in the perfect position to explain them to the rest of us! Whilst wavelet compression is an interesting and popular method, it is worth confirming that there is a real benefit in using them compared to FT compression, especially for near infrared spectra where there are few regions of flat baseline.
Tony (A.N.) Davies is getting excited by GHz NMR. These new high fields offer tantalising new areas of research but at a cost that generally requires their purchase by Government-funded centres of excellence. He argues that continued funding of such projects is essential, especially in difficult economic times.
Tony (A.M.C.) Davies starts a review of the chemometric ideas that have most excited him over the last 30 years. In this column, he looks at the use of Fourier transformation for data compression. FT can also provide the side benefit of reducing high-frequency noise.
Tony (A.N.) and Henk-Jan van Manen introduce us to the COmprehensive Analytical Science and Technology (COAST) initiative, a funding effort to counteract what was seen by industry and academia as a decline in fundamental analytical research in the Netherlands and the associated problems around producing high quality researchers and technicians.
Tony (A.M.C.) Davies and Tom Fearn describe an enhancement of the popular partial least squares (PLS) technique, powered partial least squares (PPLS), that has shown significantly better results.
Tony (A.N.) Davies and Robert Lancashire remember Bob McDonald who co-authored the first JCAMP-DX standard for infrared spectroscopy.
Tony Davies makes sure we understand “What IS and what is NOT chemometrics” and why it matters.
The Tony Davies Column once again contains a contribution from Karl Norris, who is widely regarded as the “father of NIR spectroscopy”. Karl continues to produce innovative ideas about the field and this article is no different. Building on the previous article concerning fourth derivatives, Karl has investigated the effect of varying gap sizes with some remarkable results.
Tony (A.N.) Davies is after your advice in his latest column “Your committee needs you!”. The IUPAC Subcommittee on Electronic Data Standards is keen to learn about areas where you would like to see improvements in moving your data between your analytical instruments and data analysis and reporting packages.
This Tony Davies Column is contributed by Karl Norris, known to many as “The father of near infrared spectroscopy”. He introduces his calculation method for fourth derivatives and shows how it can be used to extract instrument noise.
Tony (A.N.) Davies is impressed with the service form the UK's EPSRC National Mass Spectrometry Service Centre.
Tony (A.M.C.) Davies is again telling us to “Always look at the spectrum”. This time he uses an example from the development of a NIR spectrometer to demonstrate that one doesn’t really know what’s going on until one has “looked at the spectrum”.
Anaerobic digestion is a good solution to the joint problems of dealing with organic waste and producing “clean” energy. However, running the digesters at optimum performace is a complex business. NIR spectroscopy offers a solution to monitor a number of analytes within the reactor and in real time.
Tony (A.M.C.) Davies stresses the importance of always looking at the spectrum, even if you [think you] know there’s nothing to learn. He relates his experience with noise in NIR spectra and what he has learnt from it. He would like us all to examine spectra for abnormality before relying on automated methods.
1H NMR spectra are usually interpreted by hand, which is very time consuming, and can become a process bottleneck in fields such as high-throughput NMR. Greater automation of the spectral analysis process has become essential if NMR is to be of value as a high-throughput analytical method in the future.
Tony Davies and Tom Fearn present “A digression on regression”. They turn their attention to one of the simpler regression techniques, Classical Least Squares (CLS). As well as an explanation of the basics, they explain why it is not often used in spectroscopy, and give the pros and cons of various regression techniques.
Time for a good whinge (“complain persistently and in a peevish or irritating way”—Oxford Dictionaries Online) and to get a little controversial. Having had a year to look at the resources available to us to help educate our budding spectroscopists, I have been disappointed that much of the educational resources available online appear incomplete or outdated. For a generation of students brought up in schools with interactive whiteboards, good quality spectroscopic teaching materials of this nature are almost non-existent.
I recently “discovered” a very interesting radio programme on BBC Radio 4. It is “devoted to the powerful, sometimes beautiful, often abused but ever ubiquitous world of numbers”. A few weeks ago we were asked to say what we were doing while listening to the programme. The next week we were told that nearly 2000 e-mails had been received and this data had been given to information designer David McCandless to turn into a graphic. When this was trailed I got the impression that something new and exciting was going to be displayed and I thought that the graphic would...