Informing Spectroscopists for Over 40 Years

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Peter W.U. Appela and Kim H. Esbensenb

aSenior research scientist, www.Appelglobal.org. E-mail: [email protected]
bConsultant, independent researcher, Dr (h.c.), www.kheconsult.com. E-mail: [email protected]

Issue 31/3 (2019)

An interesting insight into, well, a week in the life of the author as a fourth-year PhD student. Katie is working on investigating a way of detecting liver damage using spectroscopy, which is “about as interdisciplinary as you can get”! I’m sure all readers will find it interesting and it may be helpful for those you know who may be considering a PhD.

Issue 31/2 (2019)

The authors look at two important areas of recycling of waste materials: concrete and plastics. If aggregates are to be recycled from concrete, the presence of pollutants (plastics, foams, brick etc.) and the degree of removal of cement mortar from the aggregates must be assessed and monitored. NIR hyperspectral imaging with PLS does a good job of both tasks.

Issue 31/2 (2019)
Depiction of underwater robot scanning a reef.

Coral reefs have been used as examples of climate change in action for decades, since the “bleaching” caused by corals stressed by heat expelling their symbiotic photosynthesising algae is such a dramatic effect. Jonathan Teague, Jack Willans, Michael Allen, Thomas Scott and John Day describe their work in developing a hyperspectral imaging system that can be deployed on a submersible remotely operated vehicle to monitor coral health through changes in their natural fluorescence

Issue 31/1 (2019)

Total reflection X-ray fluorescence (TXRF) is a “Cinderella” technique: not widely known but with great potential. The author and other members of the TXRF Workgroup are making strenuous efforts both to spread the word about TXRF and to improve communication within the TXRF community. As Ramón points out, atomic absorption or plasma spectroscopies may be the “go to” techniques for many, but TXRF is worthy of consideration.

Issue 31/1 (2019)

A fascinating update on Brillouin spectroscopy, in particular “Brillouin microspectroscopy: in search of the mechanical properties in biological systems well below a wavenumber”. They show that the Brillouin measured elastic modulus clearly varies between regions of a biological sample, even if sometimes only by small amounts. Exactly what this is telling us and for what it is most useful or relevant is currently an area of active debate and remains to be seen.

Issue 30/6 (2018)

This article provides a valuable summary of the choice of sample clean-up methods available for the quantification of small molecules in body fluids. What are the key factors? Judy outlines the principal processing methods and provides practical advice on protocol development using quantification of serum testosterone in serum samples as the model compound.

Issue 30/6 (2018)

Knowledge of the origin of bones has applications in anthropology, archaeology and forensics; NIR spectroscopy, even with handheld instruments, is showing promise in being able to differentiate bones from different species.

Issue 30/6 (2018)

Spectroscopy is widely used in forensics, but the determination of the age of documents was one application I had not considered. With a huge variety of papers and inks available, each with their own ageing profiles, and with such ageing depending on environmental factors, the determination of the age of a document is not straightforward. However, infrared spectroscopy and chemometrics may have the answer.

Issue 30/5 (2018)

Jacques Thierie’s article raises a seemingly impossible observation: that in some cases, transparency can exceed 100 %.

Issue 30/5 (2018)

Nick Polfer gives an excellent introduction to the recent technique of infrared ion spectroscopy. Ions held in the ion trap of a mass spectrometer can be probed with a tuneable light source, and its photodissociation studied as a function of the photon frequency. Nick believes that the technique will make an impact in small molecule analysis, such as metabolites, drugs and classes of molecules containing many isomers.

Issue 30/4 (2018)

Clemens Anklin gives a short history of the commercial and technical development of NMR. From the first measurement of nuclear spin in 1937 by Rabi and his 1943 Nobel Prize to recent developments in small NMR spectrometers and instrument company changes.

Issue 30/4 (2018)
Photo of caries in human teeth.

In this work we demonstrate the suitability of confocal Raman microscopy for the characterisation of carious dental tissues. Samples of enamel and dentine, presenting carious lesions in different stages of progression, were evaluated by comparing the depolarisation ratio of the PO43– symmetric stretching band at 959 cm–1 in the different tissues. Both line and area scans were performed to gauge these variations. Moreover, the obtained results were compared with the tissues’ behaviour when interacting with ultraviolet radiation, namely the induced fluorescence in some tissues. The depolarisation ratio has proven to be a valuable tool in recognition of demineralisation of both enamel and dentine due to caries. The analyses of the collagen bands in the dentine sample turned out to be more difficult to evaluate due to high fluorescence in the carious region.

Issue 30/3 (2018)

Nanomaterials find widespread applications in many fields of science and nanotechnology, especially as catalysts in the chemical, bio-nanotechnology, nano-electronics and pharmaceutical industries. Understanding the physical and chemical properties of nanoscale materials is important, not only because of the fascinating nature of the subject, but also due to their potential applicability in almost every branch of science and technology. Nanostructured materials offer interesting properties, because at the atomic or molecular scale, the physical properties of a material become size dependent due to the quantum confinement and surface states effects.

Issue 30/1 (2018)
 Illustration of a thin film solar cell based on a CIGS [Cu(In,Ga)Se2] absorber layer

In this article the question of the certification of calibration samples for the characterisation of advanced thin film materials is addressed within the framework of reliable process control or quality management purposes. Reference measurement techniques can be used in order to address the gap in appropriate certified reference materials (CRMs) for thin film analyses. They allow for qualifying out-of-production samples originating from an operating production line as calibration samples. As a template for this procedure, CIGS [Cu(In,Ga)Se2] layers, that are absorber layers for high efficiency thin-film solar cells, have been used for establishing and validating reference-free X-ray fluorescence (XRF) analysis and Auger-electron spectroscopy (AES) as reference measurement techniques.

Issue 30/1 (2018)

Different spectroscopic techniques have been combined to provide additional and complementary information for decades. Increasingly, this is being expanded beyond just two techniques and may include spatial/imaging information as well. All of which bring their own challenges. In “Multimodal imaging of cells and tissues: all photons are welcome”, David Perez-Guaita, Kamila Kochana Anja Rüther, Phillip Heraud, Guillermo Quintas and Bayden Wood report an example of these new approaches. They look at the use of infrared, Raman and X-ray fluorescence spectroscopies to obtain combined imaging data of whole algal cells and discuss how to overcome the challenges.

Issue 29/5 (2017)

Dmitry Gakamsky and Anna Gakamsky describe how fluorescence may be used to diagnose cataracts in human eye lenses. Further, it may also be able to grade cataracts and monitor the disease’s progress, which may help discover metabolic and ambient factors that influence the progress of the disease.

Issue 29/3 (2017)

Edible bird’s nest (EBN) is a highly valued food, especially in China. Due to this, there is the potential to bulk out the EBN with artificial additives to receive a higher price. This article shows yet another way in which spectroscopy is used to detect adulteration of food and prevent fraud in a quick and cost-­effective manner.

Issue 29/2 (2017)
Vince Palleschi takes a slightly different approach to reviewing the current state of laser-induced breakdown spectroscopy (LIBS). He puts the strengths and weaknesses of LIBS in context and gives some examples of industrial applications.
 
Issue 29/2 (2017)

We all know how spectroscopy and other analytical technologies have played important roles in detecting fraud and in authentication. Paper collages, or photomontages, are part of the art market that is seeing much interest amongst collectors. It is difficult to detect forgeries just through expertise. The use of NIR imaging offers a number of ways to identify forgeries or authenticate the collage non-destructively; from determining the glue used to the revealing of printing on the back of the pieces or paper, which often have been taken from books and magazines.

Issue 29/1 (2017)

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