Volatility Study of Amino Acids by Knudsen Effusion with QCM Mass Loss Detection

• Type: Article in International Scientific Journal
• Date: 2020

Authors

Stejfa, V (Author) Other; Pokorny, V (Author) Other; Miranda, CFP (Author) Other; Fernandes, OOP (Author) Other; Luis M N B F Santos (Author) FCUP

Journal

Title: ChemPhysChem

Vol. 21

Pages: 938-951

ISSN: 1439-4235

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-00R-ZM2

DOI: 10.1002/cphc.202000078

Abstract (EN): 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14