HR MAS 1H NMR spectroscopy analysis of marine microalgal whole cells

To study the use of nuclear magnetic resonance (NMR) spectroscopy as a method of classification, we performed high-resolution magic angle spinning proton (HR MAS H-1) NMR spectroscopy analysis of whole-cell samples of Dunaliella sp. (Chlorophyceae), Amphidinium carterae (Dinophyceae), Phaeodactylum tricornutum and Thalassiosira pseudonana (Bacillariophyceae). Emphasising the potential use of NMR spectroscopy as a routine analysis of microalgae we chose a straightforward procedure for culturing and harvesting, without extraction or radioactive labelling. We obtained well-resolved HR MAS H-1 NMR spectra from the 4 algae, despite the fact that our samples contained whole cells and some residual sea water. Selected parts of 5 replicate spectra from each microalga were used as input in 2 multivariate pattern-recognition strategies (principal component analysis and fuzzy clustering), both analyses showing clear grouping of the different species. Two spectra from a previous sample run (cultures grown under the same conditions) were also included, and both were correctly classified. We therefore consider HR MAS 1H NMR spectroscopy to be a potential method of classification for microalgae, with statistical data processing indicating replicability and robustness of the method.