Hidden isosbestic point(s) in ultraviolet spectra.
The existence of isosbestic point(s) in a set of UV-visible spectra is rarely exploited for quantitative or qualitative information despite its interest. Indeed, the presence of isosbestic points means a quality and quantity conservation in the global composition of samples with a given relation between the concentration of absorbing compounds or mixtures of compounds. However, in some cases, for example, when a dilution occurs, no isosbestic point appears. This work shows that a simple operation, called normalization, can reveal the existence of hidden isosbestic point(s) (IP*). This paper first summarizes the required conditions for the presence of isosbestic points. Second, it demonstrates the significance of IP* revealed by normalization. An example of the exploitation of direct or hidden isosbestic points in the environmental field illustrates the interest in and application of the technique.
Pouët
M-F
MF
Laboratoire Génie de l'Environnement Industriel, Ecole des Mines d'Alès, 6, avenue de Clavières, 30 319 Alès Cédex, France.
Baures
E
E
Vaillant
S
S
Thomas
O
O