Purity Determination of Standard Analytical Reference Materials by Differential Scanning Calorimetry

Standard Analytical Reference Materials SARMs are a high-purity representative set of compounds used in the production of explosives. Because the National Bureau of Standards has only a limited amount of these reference materials available for trace organic analysis, the United States Army Toxic and Hazardous Materials Agency USATHAMA has initiated a program for developing SARMs for use in its laboratories USATHAMA 1987. This two-part program consists of procuring and producing the high-purity reference materials and then monitoring their purity level while in storage. This paper, which is concerned with the second part of the program, reports on the method of determining the purity of the seven SARMs noted in Table 1 that are suited to differential scanning calorimetry DSC. The purity of the remaining SARMs are determined by other methods and will not be discussed further. The USATHAMA Quality Assurance program manual USATHAMA 1987 recommends a surveillance program that tests the purity of the SARMs at six-month intervals. For this project the criterion that is used for accepting the standard is that it does not have a purity level below 98 mol . If the SARM fails to meet this criterion, the central repository is to be contacted and appropriate decisions made on its status.