Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20879, USA.
Cryobiology. 2010 Dec;61(3):352-6. doi: 10.1016/j.cryobiol.2010.10.001. Epub 2010 Oct 16.
Partial phase diagrams are of considerable utility in the development of optimized cryobiological procedures. Recent theoretical predictions of the melting points of ternary solutions of interest to cryobiology have caused us to re-examine measurements that our group made for the ethylene-glycol-sodium chloride-water phase diagram. Here we revisit our previous experiments by measuring melting points at five ethylene-glycol to sodium chloride ratios (R values; R=5, 10, 15, 30, and 45) and five levels of concentration for each ratio. Melting points were averaged from three measurements and plotted as a function of total solute concentration for each R value studied. The new measurements differed from our original experimental values and agreed with predicted values from both theoretical models. Additionally, the data were fit to the polynomial described in our previous report and the resulting equation was obtained: T(m) = (38.3-2.145 x 10⁻¹ R)w + (81.19 - 2.909×10⁻¹ R)w², where w is the total solute mass fraction. This new equation provided good fits to the experimental data as well as published values and relates the determined polynomial constants to the R value of the corresponding isopleths of the three dimensional phase diagram, allowing the liquids curve for any R value to be obtained.
部分相图在开发优化的低温生物学程序中具有相当大的实用性。最近对低温生物学中感兴趣的三元溶液熔点的理论预测促使我们重新检查了我们小组为乙二醇-氯化钠-水相图所做的测量。在这里，我们通过测量五个乙二醇与氯化钠比（R 值；R=5、10、15、30 和 45）和每个比的五个浓度水平的熔点来重新进行我们之前的实验。熔点从三个测量值的平均值中得出，并作为每个研究的 R 值的总溶质浓度的函数绘制。新的测量值与我们最初的实验值不同，与两种理论模型的预测值一致。此外，数据符合我们之前报告中描述的多项式，得到的方程为：T(m) = (38.3-2.145 x 10⁻¹ R)w + (81.19 - 2.909×10⁻¹ R)w²，其中 w 是总溶质质量分数。该新方程很好地拟合了实验数据以及已发表的值，并将确定的多项式常数与三维相图相应等比线的 R 值联系起来，允许获得任何 R 值的液体曲线。
