- P-ISSN 1225-0163
- E-ISSN 2288-8985
The fiber optic fluorosensor that shows a specific selectivity for calcium ion is studied. This sensor employs protein Calmodulin(CaM) which forms a fluorescent chelate with <TEX>$Ca^{2+}$</TEX>. A dialysis membrane is used to entrap a fluorescein isothiocyanate-labeled CaM solution at the common end of a bifurcated fiber optic bundle. The sensing mechanism of this sensor is based on the shifts in the fluorescence spectrum of metal-calmodulin complexes which FCaM forms a chelate with <TEX>$Ca^{2+}$</TEX>. Upon binding with <TEX>$Ca^{2+}$</TEX>, CaM undergoes a conformational change which induces a change in the fluorescence of FCaM. This change in fluorescence signal which is measured by photomultiflier tube is related to the concentration of <TEX>$Ca^{2+}$</TEX> for calibration curve. Detection limit for <TEX>$Ca^{2+}$</TEX> and the interference effects by <TEX>$Mg^{2+}$</TEX>, <TEX>$Eu^{3+}$</TEX> and <TEX>$La^{3+}$</TEX> for this sensor are studied. Response time and life time for this fluorosensor are also investigated.