Stochastic Differential Scanning Calorimetry by Nonlinear Optical Microscopy
Stochastic Differential Scanning Calorimetry by Nonlinear Optical Microscopy
复制标题
非线性光学显微镜随机差示扫描量热法
DOI：
10.1021/acs.analchem.9b04300
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发表时间：
2019
影响因子：
7.4
通讯作者：
Simpson, Garth J.
中科院分区：
文献类型：
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作者：
Sherman, Alex M.;Geiger, Andreas C.;Smith, Casey J.;Taylor, Lynne S.;Hinds, Jeremy;Stroud, Paul A.;Simpson, Garth J.
通过二次谐波发生（SHG）成像与差示扫描量热法（DSC）的集成来记录单个晶体颗粒内的随机相变。晶体的倍频活性对非中心对称晶格内的特定分子堆积排列高度敏感，从而提供了传统成像方法无法获得的信息。因此，通过 SHG 成像很容易观察到与脱水/去溶剂化事件相关的晶格转变，并且与 DSC 测量检测到的相变直接相关。在对模型系统（尿素）进行研究后，对具有更复杂相行为的二水海藻糖进行了随机差示扫描量热法 (SDSC)。通过这些测量，SDSC 揭示了单粒子热轨迹的广泛多样性，以及仅通过 DSC 测量无法观察到的“冷相变”过程的直接证据。
Stochastic phase transformations within individual crystalline particles were recorded by integration of second harmonic generation (SHG) imaging with differential scanning calorimetry (DSC). The SHG activity of a crystal is highly sensitive to the specific molecular packing arrangement within a noncentrosymmetric lattice, providing access to information otherwise unavailable by conventional imaging approaches. Consequently, lattice transformations associated with dehydration/desolvation events were readily observed by SHG imaging and directly correlated to the phase transformations detected by the DSC measurements. Following studies of a model system (urea), stochastic differential scanning calorimetry (SDSC) was performed on trehalose dihydrate, which has a more complex phase behavior. From these measurements, SDSC revealed a broad diversity of single-particle thermal trajectories and direct evidence of a “cold phase transformation” process not observable by the DSC measurements alone.