There are a number of advantages of Raman microspectroscopy, including its the ease of its application, as in many cases no or very little sample preparation is needed and the experiments are performed at atmospheric pressure.
The study of metabolites in our sewage systems is not new, but there are particular difficulties with identifying the metabolites from new psychoactive substances, or “legal highs”. The authors describe a wide range of sample collection methodologies and their analysis with mass spectrometry.
It is not every issue that one of our articles starts with a quotation in medieval English, and it is appropriate as two of our articles cover the use of spectroscopy in cultural heritage. This is yet another field where the rich information provided by spectroscopy, along with its non-destructive nature (for many techniques), portability and ability to generate chemical images make it the answer to many questions. Kate Nicholson, Andrew Beeby and Richard Gameson are responsible for the medieval English at the start of their article “Shedding light on medieval manuscripts”. They describe the general use of Raman spectroscopy for the analysis of historical artefacts, and, in particular, their work on medieval European manuscripts and 18th century watercolour pigments. They stess the importance of checking the actual laser power density to avoid damage to priceless artefacts.
Once again developments in portable instruments lead to greater ease of use and the ability to measure far more samples. They describe the application of FT-IR, NIR and XRF spectroscopies to the development of the National Soils Inventory of Scotland, and their work in developing the use of handheld instruments, particularly FT-IR spectrometers.
Terahertz spectroscopy and imaging of Paleolithic cave etchings, 14th century paintings in a church and a mid-20th century Italian painting are all described. This helps demonstrate the versatility of the technique as well as its potential in cultural heritage preservation.
Benchtop mid-IR and NIR as well as portable NIR instruments are used for quick and non-invasive quality control of this traditional Chinese medicine. Adulterations could be detected, as well as the raw herbs and different sources of the Si-Wu-Tang. The success of the mobile NIR instrument is particularly interesting due to the growing interest in such technology for its ease-of-use and cost.
Several earthworm species secrete very small granules of calcium carbonate, and the authors think these are involved in pH regulation. These granules contain different polymorphs of calcium carbonate, including the amorphous form which is very unstable in the laboratory. To investigate this they have FT-IR spectroscopy and mapping, and are continuing this work with Ca XANES.
This article looks at the use of Raman and XRF spectroscopies to investigate the different deterioration processes caused by marine aerosols. These techniques can detect the decay compounds and the original composition of the different materials from historical buildings close to the sea, which can then be used to explain the reactions that take place on them. This helps in the development of remedial actions and preventive conservation strategies for historical buildings.
Much of the exterior surface of plants is covered by the cuticle. This plays a vital role in protecting the plant from water loss, attack by pests and pathogens and damage from UV radiation. Infrared spectroscopy is very useful in characterising cuticles, as we learn in “Infrared spectroscopy as a tool to study plant cuticles” by José Heredia-Guerrero, José Benítez, Eva Domínguez, Ilker Bayer, Roberto Cingolani, Athanassia Athanassioua and Antonio Heredia. The authors point out that, whilst still in its early stages, infrared spectroscopy has provided valuable information about the functional groups, chemical structure and arrangement and interactions of plant cuticle components.
Research into climate change takes many directions, but storing carbon or understanding its release from stores is extremely important. Pyrogenic carbon comes from the incomplete burning of biomass, and can be natural, e.g. wild fires, or man-made, e.g. the production of charcoal. The authors describe the uses of a range of spectroscopy techniques to understand the molecular structure of pyrogenic carbon and its role in the global carbon cycle.