Author
Dr Chris Marjo

The University of New South Wales Analytical Centre Supports Research and Industry

PerkinElmer has developed a partnership with the university that significantly augments the capabilities of the laboratory. The Analytical Centre is in an ideal location, providing clients’ access for application development and workshops.

Dr Chris Marjo, the manager of the Solid State and Elemental Analysis Unit in the Analytical Centre, which encompasses the Spectroscopy Laboratory, says that, “instrument use has grown significantly, as more researchers become aware of the capabilities of vibrational spectroscopy and the speed that high resolution images can now be collected”.

Access to the facilities in the laboratory is done through the on-line booking system or organized through the lab's scientific officer, Dr Anne Rich. Anne is responsible for basic competence training, overseeing research work and conducting workshops on the Raman spectrometers, FTIR Imaging and UV-Vis systems. In addition, Anne's experience of a wide range of materials and practical skills are valuable to the laboratory to aid in the development of instrumental capabilities and the scope of research that can be performed.


Dr Anne Rich using the Spotlight 400 at the Analytical Centre.


The Spotlight 400 Imaging Crystal used at the UNSW with 1.56µm resolution capability.

Asked about the range of equipment in the laboratory, Chris points out that equipment was initially focussed on Raman spectroscopy to benefit the materials science community that existed before the opening of the laboratory: “From the beginning the laboratory has supported research into new materials or nanostructures on traditional materials. A classic example is the broadening of the Raman phonon peak found in crystalline silicon at 520cm^-1 as a result of stress. Viewing changes in the silicon phonon peak provides critical information for our large photovoltaic community to understand how the surface structure of a solid influences its semiconductor behaviour. This also is a complementary technique to support data provided by our x-ray diffraction laboratory.”

Increasingly the laboratory is seeing users from a wide range of research areas. Chris explained that, “The materials community is quite diverse and we are seeing more polymer and ceramic scientists. One area of importance is in biochars. These are charcoal materials that have been aged in the soil for decades that are found to significantly boost crop yields. Researchers in the area are trying to understand how to reproduce the aging process to create biochar that is ready to be used by cultivators immediately. Of course the low cost of biochar has huge implications for crop production in developing countries. The challenge is to understand how the carbonaceous material is altered over time in such a complex mixture like soil, and to look for the presence of new chemical bonds that develop at the char-mineral interface. The Spotlight 400 FTIR Imaging Microscope has been embraced by the biochar community for this purpose. The instrument provides fast, high spatial resolution chemical imaging using its ATR-imaging crystal. It is an impressive system and complements the Raman systems we also use”.


The visible image of a biochar sample.


Chemical map measured on the Spotlight 400 showing the distribution of aromatic compounds over the biochar sample.

When asked about the training of an ever increasing number of users, Chris responded that, “One of the best decisions we made was to purchase the PerkinElmer RamanStation 400F spectrometer. The instrument is very simple to operate while providing excellent spectral performance. We have over sixty users of the laboratory with a wide range of abilities and experience. It has really helped that the RamanStation is so easy to demonstrate and use, and the functionality is robust enough so that everyone can experience this technique. It is a great introduction to the power of vibrational spectroscopy, and we are seeing many users who would never have used Raman spectroscopy adopt it enthusiastically for their research”.

The Spotlight 400 FTIR and RamanStation 400F use the same processing software allowing researchers to process their IR or Raman data in exactly the same way using Principle Component Analysis (PCA), 2D and 3D layer managers, chemi-maps and band ratios.

A significant problem in Raman spectroscopy is when the Raman scattering is overwhelmed by fluorescence in the sample, particularly in materials such as organic polymers when they are measured using UV or green lasers. This can usually be overcome by using a longer wavelength excitation source, however the efficiency of the Raman scattering process drops as the wavelength of the excitation source increases. A 785nm laser provides a good compromise between minimising fluorescence and providing efficiency for Raman scattering, making the RamanStation their key instrument for analysis of polymers, organic compounds like pharmaceuticals, and novel organic nanomaterials such as graphene and carbon nanotubes.

The range of measurement options on the RamanStation has also helped with the popularity of the instrument Chris pointed out that, “The Raman optic probe recently allowed us to safely and easily measure samples of ancient Roman glass from the Macquarie University. Also the mapping option is popular with samples that show chemical differences across millimetre to sub-millimetre length scales, such as polymer composites”. Another group at UNSW is taking advantage of the RamanStation’s versatility with “awkward” samples to measure the surface enhanced Raman scattering (SERS) on roughened gold electrodes to create new methods for trace-molecular analysis.


Danmar Gloria running SERS on the RamanStation 400F.


A roughened gold electrode that enables SERS measurements of organic species.


SERS spectrum of Danmar’s test compound 1,4- Benzenedimethanethiol.

The future of the laboratory at the Analytical Centre will see a push for more researchers in the biological and chemical areas, and this has been helped by the Spotlight’s Universal ATR system: “the UATR has been enthusiastically used by a diverse range of users who have previously had problems trying to get infrared spectra of their samples. The measurement is very simple and has been a popular tool to get rapid high-quality infrared spectra of previously difficult samples including artificial bone, ultrathin polymers, and tiny quantities of organic compounds. The ability to measure materials contaminated with water is a real advantage with this technique.”

More information on access and the capabilities of this laboratory can be found at http://www.sseau.unsw.edu.au/spectroscopy_start.htm.