Interest in Raman spectroscopy as an analytical technique that can be applied in a wide variety of fields continues to increase. The main reason for this interest is that no special sample preparation is required. However, the Raman signal is typically very weak, with only one in every 106–108 photons being scattered. This has driven the development of several enhancement techniques, e.g. Resonance Raman (RR), Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Resonance Raman Spectroscopy (SERRS), which can be used for dilute samples.
This short review shows that UV/visible spectroscopy plays a key role in the discrimination of colour in the forensic analysis of fibres and inks. The application of chemometrics, however, is vital in many cases to enhance such discrimination and to put it on a quantitative basis so providing objective justification for the conclusions of the analyst.
In 2007 we introduced our method in Spectroscopy Europe describing the identification of furs by hair digest based matrix-assisted laser desorption/ionisation time of flight (MALDI-ToF) mass spectrometry (MS). This so-called SIAM (Species Identification of Animals) method can also be used for the species determination of ancient furs.
The Foundation for Analytical Science & Technology in Africa (FASTA) is a charitable company that was established in 2005 in response to a request to provide a GC-MS to the Jomo Kenyatta University of Agriculture & Technology (JKUAT) in Nairobi, Kenya. FASTA was founded by Steve Lancaster of BP and Barrie Nixon of Mass Spec UK Ltd. The objectives of the organisation are to support scientific education, analytical research and the preservation of the environment in Africa via capacity-building and technology transfer.
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.
The scientific study of fluid inclusions goes back to the middle of the 19th century. Geochemists have sought for years to find techniques that would allow them to analyse the contents of these small liquid bubbles, but the challenge is formidable. After the progressive development of techniques that yielded results for optimal samples, Laser Ablation Inductively Coupled Plasma Mass Spectrometry has at last provided a means of analysing individual fluid inclusions in typical, rather than exceptional, samples.
This article discusses matrix-assisted laser desorption/ionisation (MALDI) enabled linear ion trap (LIT) mass spectrometry (MS) as a technique for fast and accurate tissue imaging, compared to the more traditional time-of-flight (ToF) method.
Scientific studies of artworks are an important practice in many institutions dedicated to the study and protection of cultural heritage. Applied physics and chemistry provide the scientific data necessary to characterise and understand the origin, the degradation processes and the environment in which the artwork was created or has existed.
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.
Lead exposure is an international issue. Pb may enter biological systems (as Pb2+) via food (e.g. food contaminated from cans containing Pb solders in the joints), water (e.g. use of lead pipes), air and soil (the combustions of leaded fuels have contributed to the accumulation of atmospheric and soil Pb). In the USA, the major source of ingestion in young children seems to be the dust and chips originating from old lead paint (used from 1884 to 1978).1 Foetuses and very young children (up to 36 months of age) are more sensitive than adults to relatively high blood lead levels because their brains and nervous systems are still developing and their blood-brain barrier is still incomplete. Childhood lead exposure has been correlated with school absenteeism, low class ranks, poorer vocabulary, longer reaction times and diminished hand-eye coordination, among other neurobehavioural disorders.
Inductively coupled plasma-mass spectrometry (ICP-MS) was introduced commercially in 1983 as a very sensitive analytical technique to be deployed for (ultra)trace element analysis. Compared to the previously existing techniques of atomic absorption spectrometry (AAS) and ICP-optical emission spectrometry (ICP-OES), the main advantages offered by ICP-MS over these techniques were its pronounced multi-element capabilities and substantially higher detection power, respectively.
During the last few decades, solution and solid state techniques have been utilised to obtain information about the properties of supramolecular host–guest complexes. Mass spectrometric analysis of these fragile non-covalent complexes has been focused on the determination of the molecular mass of the interacting molecules and the analysis has concentrated on the characterisation of covalent compounds. Since the invention of the soft ionisation techniques [namely ESI (electospray ionisation) and MALDI (matrix-assisted laser desorption/ionisation)] and their development for mass spectrometry (MS) instruments, the area and way that MS analysis is used have greatly changed and expanded. In particular, ESI has attained a steady position for the analysis of biomolecules, their non-covalent complexes and other rather fragile systems, which were earlier impossible to study by mass spectrometric methods. Today, MS can be employed not only for molecular weight identification purposes but also for sophisticated analyses on versatile properties of compounds. In the area of supramolecular chemistry, MS studies are becoming more and more general, although MS utilisation is still quite limited.
Over the last two decades therapeutic antibodies have become the fastest growing area in pharmaceutical biotechnology. The medical significance of these therapeutic entities is highlighted by the commercial availability of about 20 products on the market with more than 160 candidates evaluated in different clinical trials. One reason for the success of antibodies as therapeutic agents is related to the large advancement in their biotechnological production via fermentation. Nowadays titers of about 4 g L–1 in 11-day fed-batch mode using the CHO BI HEX process are achievable using CHO-cells (CHO: chinese hamster ovary).
The ultimate use of XRF for medical analysis is in vivo measurements made directly in the living patient or volunteer. It started with quantitative analysis of iodine in the human thyroid. The idea sprang from the pioneering work by Jacobsson, who developed a technique for subtraction radiology of iodine using two x-ray energies, one above and one below the K-absorption edge of iodine. Hoffer et al. realised that if that technology worked, there should be a chance to see the emitted characteristic x-rays from iodine using the semiconductor detectors, which at that time had been developed for nuclear and particle physics. In this way the first in vivo XRF analysis was done, quantifying the iodine concentration in human thyroid, typically around 400 µg g–1. The further development of the in vivo XRF technique was related to the analysis of heavy elements, first covering lead and later cadmium and to some extent also mercury in occupationally exposed workers. Platinum was also analysed to investigate uptake and kinetics of the cytostatic agent cis-platinum in tumour patients. The following section describes efforts made to study various toxic elements in vivo in occupationally exposed workers and in patients.
This article will demonstrate the use of Raman spectroscopy as a fast and easy detection system for different counterfeit erectile dysfunction drugs. The possible counterfeits analysed consisted of two Viagra® tablets, SEYAGRA-GEL containing the same active ingredient as Viagra® and two tablets claiming to contain the same active ingredient as Cialis®.
The effectiveness of these new reagents in quantitating eight states simultaneously has been determined against a set of known peptides and proteins, and is outlined in this article. The reagents were evaluated for label efficiency, fragmentation efficiency and precision and accuracy of quantitation.
Since the first experiment was performed nearly a decade ago, ultrafast two-dimensional infrared (2D-IR) spectroscopy has emerged as an exciting non-linear ultrafast laser technique for probing molecular structure and solute–solvent interaction dynamics in a range of systems of chemical and biological relevance.
Analysis of used lubrication oil for metals is commonplace in many industries. The metals analysed fall into three categories: wear metals, contaminants and additive elements. The concentration of these metals and elements can then be interpreted to schedule maintenance of engines and machinery such as construction machinery and aeroplanes. The cost of unscheduled maintenance can be high, not only in materials and parts, but also in lost profits due to downtime. Once the oil has been sampled, Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis is a very useful tool for this application.
(Image courtesy Shell Motorsport)
One of the dangerous kinds of pollution in aquatic systems is due to the dumping of materials containing heavy metals. Hence, the monitoring of heavy metals in aqueous samples is becoming increasingly important. Normally, metal concentrations in water are in the ng L–1 range, and the analytical procedures used for their determination are usually based on Anodic Stripping Voltametry (ASV) and Atomic Spectrometry, including Electrothermal Atomic Absorption Spectrometry (ETAAS), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). However, the direct analysis of some complex environmental samples like seawater presents some difficulties, mainly due to the high salinity of the matrix. Therefore, in such cases, a dilution of the sample may be necessary before the analysis, or a preliminary separation and/or preconcentration step may be required to eliminate interferences and/or to improve detection limits for metals in the low µg L–1 range. Moreover, when the analysis is performed by using solid sorbents followed by spectrophotometric techniques, an additional elution step after the preconcentration procedure is necessary to recover the species in an appropriate medium.