Crystal Nucleation Rates from Probability Distributions of Induction Times
Crystal Nucleation Rates from Probability Distributions of Induction Times
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DOI：
10.1021/cg101213q
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发表时间：
2011-01-01
影响因子：
3.8
通讯作者：
ter Horst, Joop H.
中科院分区：
文献类型：
--
作者：
Jiang, Shanfeng;ter Horst, Joop H.
已经开发了一种确定溶液中固定晶体成核速率的新方法。该方法利用了成核的随机性质，这反映在恒定过度饱和时许多测量中的诱导时间变化中。得出了概率分布函数，该函数描述了在恒定的过饱和条件下，将晶体作为时间，固定成核速率，样品体积以及将形成的核成长为可检测的大小所需的时间进行检测的概率。在1 mL搅拌溶液中，使用每次过饱和至少80个诱导时间来确定恒定过饱和诱导时间的累积概率分布。成核速率取决于衍生方程的最佳拟合对实验获得的分布。该方法已成功地用于测量两种模型化合物M-氨基苯甲酸（M-A BA）和L-齐二氨酸（L-HIS）的不同过饱和的成核速率。 M-ABA和L-HIS确定的成核速率遵循经典成核理论（CNT）预期的趋势。该行为表明，正如预期的那样，发生了异质成核。两种化合物的动力学参数A相对较低，可能表明活性异质颗粒的浓度相对较低。新方法是确定搅拌溶液中成核速率的有前途的技术。
A novel method for the determination of stationary crystal nucleation rates in solutions has been developed. This method makes use of the stochastic nature of nucleation, which is reflected in the variation of the induction time in many measurements at a constant supersaturation. A probability distribution function was derived which describes, under the condition of constant supersaturation, the probability of detecting crystals as a function of time, stationary nucleation rate, sample volume, and a time needed to grow the formed nuclei to a detectable size. Cumulative probability distributions of the induction time at constant supersaturation were experimentally determined using at least 80 induction times per supersaturation in 1 mL stirred solutions. The nucleation rate was determined by the best fit of the derived equation to the experimentally obtained distribution. This method was successfully applied to measure the nucleation rates at different supersaturations of two model compounds, m-aminobenzoic acid (m-A BA) and L-histidine (L-His). The determined nucleation rates of m-ABA and L-His followed the trend expected from classical nucleation theory (CNT). The behavior indicated that, as expected, heterogeneous nucleation occurred. The relatively low kinetic parameter A for both compounds might indicate that the concentration of the active heterogeneous particles was relatively low. The novel method is a promising technique to determine nucleation rates in stirred solutions.