Automated and computerized system for purity determination by differential scanning calorimetry

Abstract In order to evaluate and implement a widely used DSC method for purity determination, a commercial thermal analysis instrument was “interfaced” by means of an analog-to-digital converter and a communication terminal to a time-sharing computer. A computer program specifically designed for this system evaluates data for calibration purposes or calculates the purity. The program includes steps to detect the peak opening and closing, determine the area, evaluate the partial energies at various temperatures, linearize the 1/ F vs. T plot, and calculate mole % purity. The analysis (or calibration) proceeds without intervention, or at the operator's control, provides complete versatility by accommodating a choice of instrumental or computational factors, including thermal lag, heat capacity, iteration increment, and the portion of the curve (1/ F limits) to be considered. This automated and computerized system permits data accumulation and rapid purity calculation without human error, facilitating the systematic evaluation of theoretical and practical factors in the determination of purity.