Speaker
Description
This work presents advances in high-resolution chemical imaging capability at Australian Synchrotron Infrared (IR) beamline, achieved through the use of an in-house developed synchrotron macro ATR-FTIR microspectroscopic device (1). The device was developed by modifying the cantilever arm of a standard macro-ATR unit to accept germanium (Ge) ATR elements with different contact facet sizes (i.e. 1 mm, 250 µm and 100 µm in diameter). Coupling synchrotron-IR beam to the Ge ATR element (n = 4) used in this device, has the effect of not only reducing the beam focus size (improving the lateral resolution) by a factor of 4, but also reducing the mapping step size by 4 times relative to the stage step motion. As a result, the macro ATR-FTIR measurement at Australian Synchrotron IR Beamline can be performed at minimum beam size of 1.9 μm using a 20x objective, and at minimum mapping step size of 250 nm, allowing high-resolution chemical imaging analysis. It can also be coupled to a temperature control unit, allowing temperature-dependent study, as well as measurements that require a fixed temperature such as analysis of dairy products at 4 oC similar to the usual storage condition in a household fridge.
The development of the macro ATR-FTIR device has so far led to successful analysis of samples from a diverse range of research disciplinary. Key applications in food science to be presented include a range of dairy products (e.g. cheese and yoghurt), microencapsulated oil (2), plants and vegetables.
References
(1) V. K. Truong, M. Stefanovic, S. Maclaughlin, M. J. Tobin, J. Vongsvivut, M. Al Kobaisi, R. J. Crawford, E. P. Ivanova, “The evolution of silica nanoparticle-polyester coatings on surfaces exposed to sunlight,” J. Vis. Exp. 116, e54309, 1-11 (2016).
(2) Y. P. Timilsena, J. Vongsvivut, M. J. Tobin, R. Adhikari, C. Barrow, B. Adhikari, “Investigation of lipid and protein distribution in spray-dried chia seed oil microcapsules using synchrotron-FTIR microspectroscopy,” Food Chem. (2018), doi: 10.1016/j.foodchem.2018.09.043.
