As nanotechnology grows in importance, the need for rapid, easy and automated analytical methods to investigate new nanomaterials increases. Near infrared (NIR) spectroscopy has the potential to replace numerous methods for the investigation of a wide range of nanostructured materials and with particular potential in the area of PAT.
This article describes the analysis of cells from the pulp of the feather by IR spectroscopy and the possibility of using infrared imaging of intact eggs to determine bird gender.
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.
Nati Salvadó, Salvador Butí and Trinitat Pradell have used a number of techniques to investigate changes in pictorial techniques in Catalan paintings in the 15th century. The combination of different techniques is of particular value. The use of synchtrotron radiation as a light source is also an advantage.
Roumiana Tsenkova introduces us to the field of “Aquaphotomics” which she has pioneered. The potential information held by water in biological systems coupled with NIR spectroscopy’s ability to extract a large amount of information at once, means that Aquaphotomics may be of great importance in the study of living organisms.
The counterfeiting of medicines is an increasing world wide problem as a great danger to public health. Counterfeit medicines are imitations of their authentic counterparts so that both physical characterisation and chemical analysis are required to discriminate between them. In this respect, near infrared (NIR) spectroscopy is ideally suited to screening for counterfeit medicines because it is non-destructive, fast, requires no sample preparation, and provides a fingerprint of the physical and chemical composition of a product.
We have previously investigated the topographic and quantitative changes in the distribution of trace metals in spinal cords from ALS and control patients. X-ray fluorescence microscopy was used to investigate their metallic nature and distribution in single nerve cells. A deeper understanding of the neurodegenerative processes in ALS requires focus on the biochemical changes occurring in nervous tissue of such a disorder. For this purpose, we have undertaken an infrared microspectroscopy study. While metals are suggested to play a pivotal role in the pathogenesis of ALS, they typically do not occur in tissues as free ions. This results in the presence of the complex mechanisms of metal ions buffering that protect cells against their toxic effects. Metal homeostasis is regulated by several proteins. Such proteins containing metal cofactor are called metalloproteins.
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 include sound. The graphic is good but rather “ordinary” and I was disappointed. This got me thinking about how we display information. Have we made any advance in the last 25 years? Could sound be used!
<p>In last year’s <a href="https://www.spectroscopyeurope.com/td-column/and-now-something-completel...">August/September</a> issue of <em>Spectroscopy Europe</em> I wrote a column about my “discovery” of computational chemistry and asked if anyone was interested. A satisfying number of readers answered the on-line survey with very positive comments but none more so than Patrik Johansson who e-mailed me about his delight with the column and to assure me that there was “indeed a bunch of scientists out there that do work on IR (and Raman) using both experimental and computational techniques—I am one of them”! This column is the first result of the ensuing e-mail conversation and is due to Patrik. I remain excited by the possibilities of computational chemistry particularly as Patrik thinks that an approach to NIR spectroscopy is indeed possible.
For the past two centuries, the nature of the varnishes coating historical instruments has been a much debated subject. Focusing in particular on the varnishes used for coating violins made by the Italian instrument-maker Antonio Stradivari, numerous hypotheses have been raised by instrument-makers, experts, musicians and chemists, without reaching a general understanding of the ancient varnishing techniques. A few years ago, we decided to work on this topic using several complementary approaches for materials characterisation and study of historical sources (ancient varnish recipes, etc.).
The growing use of Fourier transform infrared (FT-IR) spectroscopy as a tool for quality checking amongst other things foodstuffs, industrial products and pharmaceuticals begs the question of how this technology could be applied to quantifying aspects of the internal environment of living organisms. To do this requires knowledge of the types of exudates and secretions that organisms produce. Usefully, all organisms do this and, as such, the potential to look into the internal environment of living organisms is now being realised. My particular interest is in molluscan mucus as a measure of both species identification and environmental monitoring. This interest has led onto considerations of how monitoring of mucus could be used in other organisms, particularly humans. This article hopes to provide a brief current overview of the use of FT-IR spectroscopy in the investigation of mucus from a variety of organisms.
Often, chemists are interested in the most efficient way of converting our starting materials into the desired product. A huge number of reactions proceed via the production of intermediate species which are usually short-lived and difficult to detect. Such intermediates are considered to be of great importance because it is their reactivity which can determine the outcome of a reaction and, hence, the efficiency with which the final product is made. This can have widespread importance across the whole of chemistry, ranging from pharmaceutical and organic synthesis to catalysis and materials chemistry.
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"
The enormous variability in the concentration of plant toxins and nutrients in trees, shrubs and forbs requires extensive sampling to accurately represent the nutritional and toxicological landscape and this is an ideal application for quantitative near infrared (NIR) reflectance spectroscopy. The speed of NIR spectroscopy analysis makes it ideally suited to environmental monitoring and ecological investigations where large numbers of replicates need to be measured. Several recent studies, including one focused on underwater plants on the Great Barrier Reef and the second in Bolivian rainforests, show the power of NIR spectroscopy to address large-scale variability in plant–animal interactions.
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
Following on from our previous foray into the UV-visible area of the spectrum, in this article we discuss its nearest neighbour in the spectral scale, namely near infrared (NIR) spectrometry. The NIR spectral region lies between 780 nm and 2500 nm (4000 cm–1 to 12,800 cm–1) bridging the more well-known and analytically used regions of the UV-visible (190–780 nm) and the infrared (4000–600 cm–1).
In the present study, operando infrared (IR) spectroscopy was used to investigate under realistic conditions the oxidation activity of Pt and Pd supported on different oxides, with the aim of generating mechanistic information that will be used for the design of improved formulations.
It is shown here that NIR reflection spectroscopy is able to follow even small variations of both the conversion and the thickness of thin coatings and that it accordingly can be used as an efficient in-line measuring method.
Our laboratory has received several requests from public or private institutions to solve problems related to conservation and restoration of samples from cultural heritage. A brief description of the FT-IR methodologies used to solve some of them are detailed within this article.