DSC temperature modulated

More complex temperature programmes are sometimes useful. These might combine periods of variable heating and cooling rates with isothermal periods. For example, stepwise heating can be used to detect the onset of melting under quasi-isothermal conditions (Laye, 2002). Modulated temperature DSC (MTDSC), in which the linear temperature scan is perturbed by a sinusoidal, square or saw-tooth wave, or other modulation of temperature, has a number of potential advantages over the conventional linear scan. These include increased sensitivity and resolution, and the ability to separate multiple thermal events (Laye, 2002). 

Saklatvala, R., Royall, P. G. and Craig, D. Q. M. (1999). The detection of amorphous material in a nominally crystalline drug using modulated temperature DSC—a case smdy. Int. J. Pharm., 192, 55-62. [255]... 

Craig DQM, Royall PC. The use of modulated temperature DSC for the study of pharmaceutical systems potential uses and limitations. Pharm Res 1998 15 1152-1153. 

FIGURE 4.1 Schematic representation of temperature as a function of time for conventional DSC and modulated temperature DSC. 

The book opens with the first three chapters devoted to differential scanning calorimetry (DSC), the most commonly used thermal method. These chapters cover the principles, optimal use, and pharmaceutical applications of the method. Subsequent chapters explore modulated temperature DSC, thermogravimetric analysis, thermal microscopy, microcalorimetry, high sensitivity DSC, dynamic mechanical analysis, and thermally stimulated current, all of which have attracted great interest within the pharmaceutical field. Each chapter includes theoretical background, measurement optimization, and pharmaceutical applications. 

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