This article discusses how modern inductively-coupled plasma (ICP) technology surpasses the performance of traditionally used atomic absorption spectroscopy (AAS) techniques to ensure optimal fuel quality.
Information on the detailed chemical composition, structure and morphology of environmental particles, and especially airborne particulate matter (PM), facilitate the understanding of their reactivity, sources, transport and changes of chemical species and, hence, prediction of their likely impact on the environment and human and animal health. The analysis techniques for environmental particles can broadly be divided into two groups: bulk (for example, water-soluble ionic content by means of ion chromatography for PM, elemental concentrations by means of X-ray fluorescence spectrometry for all environmental particles, chemical structural information by means of X-ray diffraction for larger environmental particles, such as sediments and sands etc.) and micro-analytical techniques, whereby the character of any single particle can be probed.
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.
Spectroscopy is the measurement of the interaction of radiation with matter before or after spectral dispersion. This has been studied variously by physicists and chemists, has wide applications outside these traditional disciplines and cannot be owned by any particular community. The subject embraces both science (including mathematics) and technology (including computing) and contains many examples of differences, not always understood, between these cultures. It illustrates the unchanging and universal character of the relevant science, which is increasingly revealed by advances in the relevant technology.
We conceive selected ion flow tube mass spectrometry, SIFT-MS, primarily as a real-time, absolute, analytical technique that can meet the challenge of the immediate analysis of humid exhaled breath for rapid clinical diagnosis and therapeutic monitoring. This objective has certainly been achieved and the application of SIFT-MS has quickly been expanded into many other areas where real time, immediate analyses of trace compounds in air are desired, as we have demonstrated in recent reviews and which we summarise at the end of this article.
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.
Imaging of organic and inorganic constituents of tablets represents a considerable challenge and no single spectroscopic approach can provide definitive characterisation of all components and/or satisfy key measurement criteria such as sensitivity, specificity, resolution and speed of analysis. Laser ablation in combination with ICP emission spectrometry represents a powerful new tool for imaging elemental distribution in pharmaceutical tablets.
Doping control authorities and sports drug testing laboratories are frequently confronted with the illicit use of performance-enhancing therapeutics and therefore various analytical strategies have been developed to detect a misused drug and/or its metabolic product(s) in blood or urine specimens. Besides the administration of clinically approved drugs prohibited in sports, new drug candidates currently undergoing early or advanced clinical trials have also been the subject of investigations concerning their prevalence and abuse by athletes.
Non-destructive, high resolution, sediment core scanners incorporating X-ray fluorescence (XRF) spectrometry are now widely used by sub-disciplines in the earth and environmental sciences and have revolutionised the analysis of sediment cores. These powerful instruments allow the cores to be analysed rapidly with virtually no sample preparation. They can record along-core variations for many elements in the Periodic Table from Al to U and detection limits down to a few ppm can be achieved in favourable conditions depending on the acquisition dwell time.
The problem of detecting, recognising and identifying explosives at significant standoff distances has proved one of the most difficult—and most important—challenges during recent years, being today, one of the most demanding applications of spectroscopic techniques. The limited number of sophisticated available techniques potentially capable of standoff detection of minimal amounts of explosives is based on laser spectroscopy. Of the recently developed techniques, Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS) are considered significant for their potential for homeland defence applications.
Here, we focus on new trends in Raman spectroscopy to improve in vivo diagnosis. The use of Raman spectroscopy for real-time diagnosis of medical disease without the need for biopsy is among the most exciting and clinically relevant applications; four recent reports are presented. First, an approach to reduce fluorescent background of lung tissue in combination with a biomedical filtered Raman fibre optic probe was introduced in 2009 by Magee et al. Second, a fibre optic probe was developed for the CARS variant of Raman spectroscopy. Third, functional metal nanoparticles and carbon nanotubes were applied to a small animal model to collect Raman spectra non-invasively utilising the surface enhanced Raman scattering (SERS) effect. Finally, spatially offset Raman spectroscopy (SORS) has been presented as another non-invasive Raman-based method to probe deep bone subcutaneously in an animal model.
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.).
This year the International Barcode of Life initiative (IBoL) plans to begin an ambitious programme to barcode the DNA of more than five million specimens representing at least 500,000 species in five years. Molecular barcodes exploit the fact that molecular sequences offer an independent method to identify a sample. Such molecular barcodes have widespread application in systematics, biodiversity, forensics and even food science. Molecular barcodes tend to be based upon DNA, which with the advent of new technologies offers a fast and efficient means of identification. Proteins too have been used in the past for molecular identification, most commonly exploiting the exquisite specificity of antibodies to discriminate targeted proteins. Recently the idea of using protein mass spectrometry to fingerprint samples has been used to target samples in which processing or decay has destroyed the DNA.
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.
The intense development of industrial and urban areas in the absence of accurate measures to control pollution sources is often the cause of several environmental problems: dispersed and undetected chemical waste problems, in particular trace elements such as heavy metals, may cause freshwater, soil and water-table contamination. Such events are rarely detectable by sporadic analyses on water samples, since trace element concentrations are often below the instrumental detection limits and/or quickly change in space and time.
In urban environments, where the majority of the human population lives, air pollution is a major threat to human health. In many countries and regions of the world, this has led to the implementation of regulations to control the emissions of air pollutants and limits for the allowed concentrations of different types of air pollutants. The limits are set at levels at which harm to the health may occur if the limits are exceeded. One of these pollutants is aerosol particles. In most cases, the environmental quality standards limit is set to a certain mass concentration of particles of a certain size.
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.
An NMR tour of Mediterranean anise-flavoured alcoholic beverages.
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.
This article highlights the versatility of the developed methodology for the measurement of arsenic species in a range of materials from Devon Great Consols (DGC), one of many former mining sites in the south- west of England.