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Updated: Sep 2, 2025
Sample Preparation in Quartz Crystal Microbalance Measurements of Protein Adsorption and Polymer Mechanics
Published on: January 22, 2020
In situ discrimination of polymorphs and phase transformation of sulfamerazine using quartz crystal microbalance
Li-Shang Liu1, Jong-Min Kim2, Woo-Sik Kim3
1Shandong Provincial Key Laboratory of Detection Technology of Tumor Markers, College of Chemistry and Chemical Engineering, Linyi University, Linyi, 276005, PR China; Functional Crystallization Center, Department of Chemical Engineering (Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, 446-701, South Korea.
Abstract:
A novel strategy utilizing the quartz crystal microbalance (QCM) was developed for the in situ discrimination of polymorphic nucleation (form-I and form-II) and phase transformation of sulfamerazine (SMZ) in cooling crystallization. According to Ostwald's rule of stages, metastable form-I of SMZ is first nucleated and then shifted to stable form-II by solution-mediated phase transformation. Through surface modification with the self-assembled monolayer technique of a functional group, QCM distinctively detects the formation of the two polymorphs. The results indicated that -NH2 (among the several functional groups tested) selectively accommodated stable form-II on the QCM sensor's surface and completely prevented the adsorption of metastable form-I on the surface. Therefore, the-NH2-terminated QCM detected the formation of form-I only using the solution viscosity variation on the surface. However, it monitored the nucleation and growth of form-II via the solid mass change on the surface during the phase transformation of form-I to form-II. This strategy suggests a new and precise solution for in situ discrimination of SMZ polymorphs and their phase transformation.
