Nitrite optical sensing from core-shell structured nanosensors functionalized with rhodamine molecules

The present work was focused on two recyclable nitrite sensing nanosensors constructed by the combination of a magnetic guiding component, a silica molecular sieve supporting matrix and traditional rhodamine chemosensors. Their core-shell hybrid structure was confirmed by means of electron microscopy, mesoporous analysis, magnetic property, IR spectra and thermal degradation analysis. Detailed analysis suggested that the emission of these two composite samples came from their rhodamine derived chemosensors. Their emission was quenchable by nitrite, following a static quenching mechanism. These two composite samples had low LOD values around 0.7 mu M. After being used, these composite samples could be recovered by sulphamic acid, realizing their recyclability.