Flinders Institute for Nanoscale Science and Technology, Flinders University, College of Science and Engineering, GPO Box 2100 Adelaide, South Australia 5001, Australia.
Analyst. 2018 Oct 8;143(20):4930-4935. doi: 10.1039/c8an00948a.
Diatoms Thalassiosira pseudonana and Chaetoceros muelleri (Bacillariophyceae) were cultured at three different salinities (26, 36 and 46 practical salinity units (PSU)) and their silica content examined using natural abundance 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The samples were investigated using both single pulse (SP) and cross-polarisation (CP) MAS experiments. In addition, samples of T. pseudonana were examined using variable contact time CP MAS experiments allowing the dynamics (TSiH and T1rρH) of CP to be determined. Comparison of SP and CP results revealed a change to a less condensed silica state when diatoms were cultured at salinities away from optimal (36 PSU). Further, an increased amount of organic material (but not its composition) was determined to be present for such samples affecting CP experiments. The location of the organic material, on the diatom surface or within the frustule, was unable to be determined.
利用天然丰度 29Si 魔角旋转（MAS）核磁共振（NMR）光谱法，在三种不同盐度（26、36 和 46 实用盐度单位（PSU））下培养了硅藻塔胞藻和角毛藻（Bacillariophyceae），并检查了其硅含量。使用单脉冲（SP）和交叉极化（CP）MAS 实验对样品进行了研究。此外，使用可变接触时间 CP MAS 实验检查了塔胞藻的样品，从而确定了 CP 的动力学（TSiH 和 T1rρH）。SP 和 CP 结果的比较表明，当硅藻在偏离最佳盐度（36 PSU）的条件下培养时，硅的状态会变得不那么密集。此外，确定了在这种情况下存在更多的有机物质（但不是其组成），这会影响 CP 实验。无法确定有机物质位于硅藻表面还是壳体内。
