In an exclusive interview with EuroLab, Dr Adrian Knowles reveals the latest advances and new applications of Raman spectroscopy.
Raman spectroscopy is becoming much more accepted as a tool for analytical and industrial testing, offering benefits to the user in the range of samples that can be analysed, the speed of analysis and, importantly, in the information content that the analysis can provide. Commenting on this evolution, Dr Adrian Knowles, Raman product manager for Horiba Scientific, states: “It can now offer value for money and a return on investment for the industrial lab that is superior to many other techniques, saving on analysis time and minimised consumables, even when compared to traditional techniques such as NIR and FTIR spectroscopy.”
When it comes to particular applications of this technology, Knowles reveals that it is becoming popular in a variety of areas. “Raman is a very powerful and versatile technique and we are seeing the take-up of the technology in numerous application areas,” he begins. “The key to success is to demonstrate the real-world benefits of this still young technique. Pharmaceutical analysis (content uniformity, troubleshooting and fake detection) is one common use, but it’s certainly not the limit. Nanomaterials (studying quality of batch production, through to bio-toxicity), polymers (quality control, reaction troubleshooting), forensics, even mining and geology are all now seeing uses for the technology.
“The new generation of instruments such as Horiba’s XploRA Plus and XploRA One has been vital to enabling this progress. These instruments offer a more cost-effective tool that is powerful and versatile enough to actually analyse the materials with speed and good limits of detection, but in a way that is simple to operate. They feature ‘one click’ operation and databases that provide real answers and not just spectra.”
Strengths of Raman in analytical testing
Knowles suggests that Raman can be split into several types of analysis: micro-analysis; bulk macro analysis; and remote sampling. He says: “Many lab-based instruments can offer all of these methods in a single platform, so the possibilities are almost limitless.
“For instance, the modern XploRA Plus Raman microscope has the ability to analyse discrete particles, thin layers or sample domains to the sub-micron level, thus it can really drill into a sample’s composition – combining the Raman chemical analysis with specific information on sample homogeneity. Techniques such as SWIFT (fast Raman imaging) can provide a new way of viewing a sample, giving a ‘chemical image’, which complements and can even replace the traditional optical microscope image.”
Knowles also observes that, “the use of Horiba’s Transmission Raman accessories has been a good way to show the other side of the equation and is an apt illustration of the robust bulk sampling abilities of Raman spectroscopy. This approach does not require the complex calibration and re-calibration of say, NIR spectroscopy and it doesn’t have the same limitations on surface effects or aqueous water interference that mid FT-IR suffers from.”
When asked what has changed in the technology to make it more accepted in the lab, and why is it now often classed as a facilitating technique, Knowles explains that these developments can be attributed to two key points. “The differences in the technology have been very marked over the last few years,” he begins. “The equipment footprint has significantly reduced. The XploRA series is a prime example of this, as it offers a very high level of performance but at a fraction of the lab bench footprint of the older generation of instruments. Even handheld and portable models with basic pass/fail Raman analysis are now available, and whilst limited in their scope (and certainly not replacing true analytical instruments), they do offer remote point of need sampling.
“But most importantly, it is the software and automation that has really advanced and opened up access to the technique. With a simple ‘one click’ process users can obtain a Raman analysis (even self-optimising the measurement parameters), search a database and obtain a real and validated answer in seconds.”
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