In this article, three real-life Raman quantitative and semi-quantitative analysis applications are discussed. These applications showcase the versatility of Raman spectroscopy and the potential impact that it can make in various industries.
The inability to have children can cause great heartache for many couples, with infertility affecting at least one-in-six couples in Britain and one-in-eight in the United States. The most common cause is male infertility, usually characterised by sperm with little or no mobility. One treatment commonly used in these cases is in vitro fertilisation (IVF). This involves injecting sperm into the egg in a laboratory.
In the development of solid state drugs, pharmaceutical companies are recognising the need for early screening of polymorphic forms of drug compounds. Polymorphism is the ability of a molecule to exist in more than one stable or meta-stable crystalline state. Traditionally, pharmaceutical labs have employed XRD and thermal analysis techniques.Thermo Electron Corporation presents a new method for polymorph screening, salt selections and crystallisation studies with the combination of the new OMNIC Array Automation software and its FT-Raman and dispersive Raman spectrometers. Raman offers several advantages, including high sensitivity to molecular geometry, microtiter well-plate sampling and high throughput data collection.Thermo's new Array Automation controls the screening process and rapidly sorts polymorphs in to visually identifiable groupings. This enables the analyst to rapidly sort known crystalline forms and outliers requiring further study. Early adopters have reported that processes requiring hours of manual labour can now be performed in minutes.Thermo Fisher Scientific Issue: 17/03 RSN: 132
Astronomers are increasingly turning to Raman spectroscopy to help them understand the formation of the planets and of our solar system. Meteorites are a vital source of information, as their composition provides evidence of their origin and conditions of formation. Renishaw's structural and chemical analyser (SCA) allows Raman spectroscopy to be performed simultaneously with scanning electron microscopy (SEM), enabling the unambiguous identification of atomically similar meteorite constituents.
The illustration shows an SEM image of a 660 µm × 413 µm area of a meteorite slice, which reveals the grains and morphology of the sample. Energy dispersive spectroscopy (EDS) of the dark regions indicates the presence oxygen, magnesium and silicon, with two distinct species containing different ratios of the elements. Raman spectroscopy identifies the species present as the silicates, enstatite (Mg2Si2O6) and forsterite (Mg2SiO4).Renishaw Plc Issue: 17/03 RSN: 130
For scientists trying to interpret a Raman spectrum, matching an unknown sample to a spectrum database is the most common approach. However, an exact match cannot always be found. Thus, it is useful to also incorporate a "functional group analysis" approach.
The use of software such as Bio-Rad's AnalyzeI™ Raman (in the KnowItAll® Informatics System) can assist in this process to:Find functional groups that match peaks in an unknown Narrow a spectral search result Look for conflicts in a particular region Determine if you need to run a more strongly absorbing sample to enhance confirmation of weak peaks
To perform the analysis, simply load a spectrum and click on a peak of interest to generate a list of functional groups possible at that position. Alternatively, draw a structure to break it into its component functional groups. The software generates results from a knowledge base that contains over 200 functional groups and over 700 interpretation frequencies.Bio-Rad Laboratories Issue: 17/03 RSN: 131
Chemical identification and composition verification are becoming increasingly important in pharmaceutical manufacturing and research. In addition to identifying the chemical composition of active ingredients in formulations, it is often necessary to indicate the crystalline form of the substances of interest.
Polymorphic forms of active ingredients exhibit the exact same empirical and chemical formula, but can affect the way in which the active ingredient bonds to other molecules. This can affect the formulation's ability to produce the desired biological effect or influence its dissolution, thereby altering or even eliminating desired drug delivery.
The Nicolet™ Almega™ XR dispersive Raman spectrometer from Thermo Electron Corporation offers the ability to analyse both the chemical and physical form of polymorphic compounds. Raman is highly sensitive to molecular backbone and branching structures. It can be used to analyse chemical identity and confirm polymorphic form, as well as quantitatively predicting the relative amounts of the various forms in a single formulation.Thermo Fisher Scientific Issue: 16/06 RSN: 132
Instruments SA has released a range of new application notes detailing the use of the latest LabRam Raman systems for various forms of analysis. Applications such as confocal Raman microscopy of integrated circuits, analysis of hard carbon films and the identification and mapping of different phases in polymer blends are included.HORIBA Jobin Yvon Ltd Issue: 11/04 RSN: 203