Articles

In quantitative analysis, is it better to weigh materials when making up standard solutions or to use volumetric techniques? Traditionally, the answer has been “volume”, however, things may not be as straightforward as they seem. Henk-Jan and colleagues have conducted a new experiment, using robots for both sample preparation and spectroscopic analysis which may provide a definitive answer. Unfortunately, the answer must wait for publication of their paper, but Tony and Henk-Jan’s history of this question makes interesting reading nevertheless.

The Sampling Column points out that incorrect sampling is irreversible: no amount of chemometrics or further samples will be able to produce a valid model if the sampling is not representative. This applies in flowing PAT analyses as much as in static.

Whilst the major components of food are usually non-fluorescent, many minor food components that affect its nutritive, compositional and technological quality are fluorescent. Given its sensitivity, ease of use and non-destructive nature, this makes it useful in many applications around monitoring food processing and in fundamental food research.

Tony (A.M.C.) Davies continues on his last furlong, this time considering “Classification and identity testing”. As well as some interesting insights into the analytical lab in the late 1960s, he gives his opinion on various chemometric techniques and on identity testing, as well as thoughts on future development.

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 (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 Davies makes sure we understand “What IS and what is NOT chemometrics” and why it matters.

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.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.