P-Campus-Ringvorlesung am 22.06.23
Am 22. Juni findet der nächste Vortrag der P-Campus-Ringvorlesung 2023 statt. Dr. Kay Sowoidnich vom Ferdinand-Braun-Institut spricht online via Webex zum Thema "Raman spectroscopy and imaging of fluorescent phosphate-containing samples – Case study for soil and bone inspection".
Die Vorlesung beginnt um 15:00 Uhr und ist kostenfrei.
Raman spectroscopy is an established technique for simple, non-destructive and molecule-specific analysis in many applications, e.g. the assessment of phosphate species. However, fluorescence interference can potentially mask weak Raman signals thus limiting the information content. Here, we present selected concepts to address the fluorescence issue. Confocal Raman microscopy can focus on small sample regions in the micrometer range while shielding out fluorescence from out-of-focus regions. For highly fluorescent samples, shifted excitation Raman difference spectroscopy (SERDS) can provide a suitable way to separate Raman signals from interferences using a physical approach with two slightly shifted laser wavelengths.
Detailed knowledge about soil composition is of global importance to determine fertilizer demands and to enable efficient nutrient management. Results show the spatially-resolved imaging and identification of calcium phosphates amended to three different soils. Moreover, using soil collected from an agricultural field, the identification of 13 different soil minerals and the capability for quantitative analysis, e.g. to predict the organic matter or carbonate content was demonstrated.
Molecule-specific bone analysis has implications in many areas including medicine, animal health and forensics. Measurements conducted on bone tissue (chicken thigh and pork metacarpal) demonstrate the identification of mineral (calcium phosphate) and organic (collagen) bone constituents despite strong fluorescence interference. It was shown that the mineral-to-collagen ratio is higher in chicken bone compared to pork bone thus being a suitable indicator to distinguish between these two bone types.
A portable SERDS system has been developed in-house and on-site pilot investigations on an agricultural field will be presented as application example.