Optosensores en flujo : de la regeneración a la renovación de la superficie sensora

Abstract

[EN] In this Memory it is showed the development of ten spectroscopic continuous flow sensors for the automatic determination of organic and inorganic species of environmental and pharmaceutical interest. These sensors have been classified according to the developed methodology in sensors with or without renovation of the sensing surface. Three flow sensors without renovation of the sensing surface ha ve been developed using this methodology, one of them uses spectrophotometric detection and two of them spectrofluorimetric detection, based on the measurement of the absorbance in UV region or the intrinsic fluorescence of the analytes. In all these cases it is not necessary previous derivation reactions.

The seven developed sensors with renovation of the sensing surface are based on the concept of Bead Injection Spectroscopy. The use of this methodology is justified when the species of interest is strongly retained on the sensing surface and the regeneration of the support is not possible in suitable conditions or becomes extraordinarily difficult. The methodology used in these seven sensors is based on the injection of an exact volume of a homogenous beads suspension in a flow injection analysis system with spectroscopic detection. The beads (solid support) are loaded in the flow cell placed in the detection zone of a nondestructive spectroscopic detector. At the end of the analysis, the beads are discarded by reversing the flow and instantaneously transported out of the system, being replaced the sensing surface after each measurement.

In all cases, a great study of the experimental variables that can affect this type of sensors has been performed. Next, the sensors were calibrated for the corresponding analytes, finding a calibration equation that allowed relating the values of the analytical signals with the concentration of the sample. The method used in all the cases was the univariante ca libration. Studies of interferences were made to know the response of the sensor in presence of the organic and inorganic compounds that usually accompany the analytes in the rea l samples. In the case of serious interferences occurring, appropriate modifications for their elimination were designed. Finally, the proposed sensors were applied to the determination of these analytes in samples of different nature. The results confirm the validity of the proposed sensors.