Quartz Crystal Microbalance Data

Baxamusa, S H

Lawrence Livermore National Laboratory

关键词: Quartz;    Sensitivity;    Microbalances;    42 Engineering;    Solvents;   

DOI  :  10.2172/1033737
RP-ID  :  LLNL-TR-518791
RP-ID  :  W-7405-ENG-48
RP-ID  :  1033737

美国|英语

来源: UNT Digital Library

【 摘 要 】

We are using a Qpod quartz crystal microbalance (manufactured by Inficon) for use as a low-volume non-volatile residue analysis tool. Inficon has agreed to help troubleshoot some of our measurements and are requesting to view some sample data, which are attached. The basic principle of an NVR analysis is to evaporate a known volume of solvent, and weigh the remaining residue to determine the purity of the solvent. A typical NVR analysis uses 60 g of solvent and can measure residue with an accuracy of +/- 0.01 mg. The detection limit is thus (0.01 mg)/(60 g) = 0.17 ppm. We are attempting to use a quartz crystal microbalance (QCM) to make a similar measurement. The attached data show the response of the QCM as a 5-20 mg drop of solvent evaporates on its surface. The change in mass registered by the QCM after the drop evaporates is the residue that deposits on the crystal. On some measurements, the change in mass in less than zero, which is aphysical since the drop will leave behind {>=}0 mass of residue. The vendor, Inficon, has agreed to look at these data as a means to help troubleshoot the cause.