In situ discrimination of polymorphs and phase transformation of sulfamerazine using quartz crystal microbalance.

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.

Quantitative control of CaCO growth on quartz crystal microbalance sensors as a signal amplification method.

The surface crystallization of CaCO on gold was monitored by a quartz crystal microbalance (QCM). Quantitative control of the grown crystals was realized by adjusting the ratio of two functional groups, -N(CH) and -COOH, on SAMs. Crystals with uniform size, morphology and polymorphism were obtained.

Ultrasensitive Detection of DNA and Ramos Cell Using In Situ Selective Crystallization Based Quartz Crystal Microbalance.

Herein we introduce the first successful assay of biomolecule by in situ selective crystallization based quartz crystal microbalance (QCM). Selective crystallization of CaCO on QCM sensor surface was utilized as an efficient mass amplification strategy and enhanced the sensitivity of QCM significantly. High specificity is guaranteed by the cooperation of two functional groups: -N(CH) and -COOH.

Quartz Crystal Microbalance Technique for in Situ Analysis of Supersaturation in Cooling Crystallization.

A quartz crystal microbalance (QCM) is used as a novel in situ strategy for analyzing the supersaturation profile during cooling crystallization. The main concept is based on preventing any solid mass loading on the QCM sensor by modifying the sensor surface. As a result, the QCM responses only depend on the solution concentration changes during the crystallization.

Simple and reliable quartz crystal microbalance technique for determination of solubility by cooling and heating solution.

A quartz crystal microbalance (QCM) is presented as a promising technique for determining the solubility and induction of nucleation via the cooling and reverse heating of a solution. When cooling and heating a solution, the resonant frequency (F) and resonant resistance (R) of the QCM responses change significantly due to vibrational loss related to the viscous and elastic friction that depend on the solution viscosity and solid mass on the sensor, respectively. Thus, obvious refraction points appear in the QCM response profile at the induction point of primary nucleation during cooling crystallization and at the saturated point during heating dissolution.

Quartz crystal microbalance technique for analysis of cooling crystallization.

A quartz crystal microbalance (QCM) technique is developed for the in situ analysis of the cooling crystallization processes of crystal nucleation and growth. In contrast to conventional techniques based on property changes in the solid or solution phase, the proposed QCM technique simultaneously exploits property changes in both the solid and solution phases, such as the solid mass and liquid viscosity, to analyze the crystallization processes. When initially cooling the solution, an increase in the solution viscosity is reflected in the QCM responses for the resonant frequency and resonant resistance.