RESUMEN
About ninety empirical functions for the representation of chromatographic peaks have been collected and tabulated. The table, based on almost 200 references, reports for every function: (1) the most used name; (2) the most convenient equation, with the existence intervals for the adjustable parameters and for the independent variable; (3) the applications; (4) the mathematical properties, in relation to the possible applications. The list includes also equations originally proposed to represent peaks obtained in other analytical techniques (e.g. in spectroscopy), which in many instances have proved useful in representing chromatographic peaks as well; the built-in functions employed in some commercial peak-fitting software packages were included, too. Some of the most important chromatographic functions, i.e. the Exponentially Modified Gaussian, the Poisson, the Log-normal, the Edgeworth/Cramér series and the Gram/Charlier series, have been reviewed and commented in more detail.
Asunto(s)
Cromatografía , MatemáticaRESUMEN
The formation of complexes between iron(III) and two ligands of possible relevance to chelation therapy, 2-hydroxynicotinic acid and 3-hydroxypicolinic acid, in aqueous 0.6 m (Na)Cl at 25 degrees C, has been investigated by means of potentiometric titrations and UV measurements. In both cases several mononuclear complexes and their deprotonation products are formed.