This work presents a new Knudsen effusion apparatus employing continuous monitoring of sample deposition using a quartz‐crystal microbalance sensor with internal calibration by gravimetric determination of the sample mass loss. The apparatus was tested with anthracene and 1,3,5‐triphenylbenzene and subsequently used for the study of sublimation behavior of several proteinogenic amino acids. Their low volatility and thermal instability strongly limit possibilities of studying their sublimation behavior and available literature data. The results presented in this work are unique in their temperature range and low uncertainty required for benchmarking theoretical studies of sublimation behavior of molecular crystals. The possibility of dimerization in the gas phase that would invalidate the effusion experiments is addressed and disproved by theoretical calculations. The enthalpy of sublimation of each amino acid is analyzed based on the contributions in two hypothetical sublimation paths involving the proton transfer in the solid and in the gas phase.

中文翻译：

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用克努德森渗出与QCM质量损失检测法研究氨基酸的挥发性。

这项工作提出了一种新的克努森（Knudsen）渗漏设备，该设备使用石英晶体微量天平传感器对样品沉积进行连续监控，并通过重量分析法确定样品的质量损失进行内部校准。该仪器用蒽和1,3,5-三苯苯进行了测试，随后用于研究几种蛋白氨基酸的升华行为。它们的低挥发性和热不稳定性极大地限制了研究其升华行为和现有文献数据的可能性。这项工作中提出的结果在其温度范围内是独一无二的，并且对于确定分子晶体的升华行为的理论研究所需的不确定性低。气相二聚化使渗出实验无效的可能性已通过理论计算得到解决和证明。基于两种假设的升华路径中涉及固体和气相中质子转移的贡献，分析了每种氨基酸的升华焓。