DIFFERENTIAL SCANNING CALORIMETER UPGRADE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. ACERT possesses a Perkin-Elmer model DSC-4 calorimeter which we occasionally want to employ for calorimetric measurements on samples provided by center users. This instrument is almost 30 years old and, although the calorimeter section functions well, the control interface, dedicated operating computer and data storage media are only of historical interest. Consequently, we were no longer able to store data or perform analysis with the original computing platform. To revitalize this otherwise functional instrument, we investigated the availability of a commercial aftermarket computer/control system upgrade (Instrument Specialists, Inc.) but found the available package of computer hardware with data analysis software to be both more comprehensive and more expensive than our requirements justified. Noting instead that our need was elementary, i.e., only the collection of heat flow vs. temperature data, we undertook an examination of the P-E DSC-4 apparatus and determined that extraction of appropriate signals and providing a means for their conversion to data for analysis and storage would be a reasonably straightforward task. Subsequently, we have updated the computer to a contemporary IBM-compatible unit and added an external, USB-interfaced universal data acquisition device (National Instruments, Inc.). Because we did not have access to information describing the Perkin-Elmer proprietary control signals, data collection is for now initiated by manual operation of the DSC-4 control and sample chasses at which time the computer begins collecting data. The data that is converted with the current arrangement comprises the DSC-4 heat flow rate and temperature analog signals, and a digital signal corresponding to temperature marker occurring every 10 ¿ C. We plan to develop by the end of the summer a suite of basic calorimetry analysis software routines for semiautomated analysis of the DSC-4 data.