Non-structural carbohydrates [NSC] are important to tree growth and survival. Their quantification can be achieved by several analytical methodologies of varying accuracy. I am currently applying one of these – LC-MS – to elucidate the structure of algal oligosaccharides. However, these advanced analytical techniques require some fairly high-tech equipment and some careful sample preparation.
Recently it has been proposed that near-infrared spectroscopy can be used to quantify NSC with no sample preparation beyond homogenisation in a ball mill, or similar (Ramirez et al 2015). One of my students wants to try this method so I showed her how to put samples into the Fourier Transform InfraRed [FTIR] spectroscope. The referenced paper used a rigorous process of parallel biochemical analysis to determine the NSC content of the samples analysed and used these to determine the relationship between the NSC content and the FTIR properties. I have proposed a standard analytical process to eliminate this complex validation process, known as Standard Addition. Using this technique the student will add varying concentrations of the different NSC components to her samples and determine how this addition affects their FTIR properties. This should obviate the need to conduct biochemical or chemical analysis in parallel.
Ramirez et al, 2015: Near-infrared spectroscopy (NIRS) predicts non-structural carbohydrate concentrations in different tissue types of a broad range of tree species. Methods in Ecology and Evolution 2015, 6, 1018–1025 doi: 10.1111/2041-210X.12391