Titration microcalorimetry technique

Numerous attempts to determine the equilibrium constants using titration microcalorimetry failed, due to solubility problems encountered at the higher concentrations of catalyst and dienophile that are required for this technique. 

The development, manufacturing, and storage control of drugs has direct bearings on medicine, and some important uses of calorimetry in the pharmaceutical industry will therefore be pointed out. As a result of recent developments in microcalorimetry, techniques for thermodynamic characterization of binding reactions between drugs and biopolymers have become readily accessible. To an increasing extent, titration microcalorimetry is now used in the pharmaceutical industry. 

Discussion of the effect of ligand structure on protein-carbohydrate affinity requires an evaluation of complex stability constants. A munber of biophysical techniques are appropriate for the study of protein-carbohydrate interaction many of the more enlightening strategies are the topics of separate chapters elsewhere in this volume. We describe below three techniques used extensively in glycobiology— inhibition of hemagglutination, enzyme-linked lectin assay (ELLA), and isothermal titration microcalorimetry—and we consider the types of information provided by each technique in order to facilitate appropriate interpretation of the data. 

Several methods have been used to determine the surface acidity of solid acids, but each method has its limitations. Common methods are titration with the Hammett indicators, temperature-programmed desorption (TPD), adsorption microcalorimetry, catalytic test reactions, and IR and NMR spectroscopies. These techniques exhibit several advantages and disadvantages. 

Wadso (11) states that one of the main applications for isothermal microcalorimetry is the investigation of noncovalent binding processes by means of titration techniques. This use of the instrument employs a cell with a liquid (pure liquid, solution, or suspension), which is stirred. It is then possible to inject small quantities of another liquid and to measure the heat flow from the events that take place. One event will be the dilution of the injected material into the fluid in the cell thus, it is necessary to correct for these dilution effects. Other responses will be due to any interaction between the injected material and the solute or suspended matter in the cell. If it is assumed that the titrated material all interacts with the solute and suspended material, then there will be almost zero free concentration of the titrated sample. This will allow calculations of the enthalpy for the binding process and the stoichiometry. 

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