title: Conditions for calibration of an isothermal titration calorimeter using chemical reactions.
abstract: The reaction of protonation of 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) is a suitable one for the calibration of isothermal titration calorimeter (ITC), providing that experimental conditions are appropriately chosen. The conditions and methods for handling experimental data from a nanowatt-ITC are discussed. Also, the binding of Ba(2+) to 18-Crown-6 is successfully used to check the accuracy and precision of the chemical calibration performed with TRIS. This latter reaction has the additional advantage that the data can also be used for a check on the determination of the value of a binding constant. The anomaly of the first injection in ITC is analyzed and, by combining calorimetric and spectroscopic measurements, it is shown that it mainly results from a backlash effect of the syringe plunger rather than from a diffusion effect.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Catania, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Sgarlata
authors.forename: Valeria
authors.initials: V
authors.lastname: Zito
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arena