Calix 4 arene Derivative Capped Quantum Dots for Fluorogenic Sensing of Aromatic Analytes

Abstract

newline Quantum dots (CdSe and CdS) were synthesized and capped with Calix[4]arene derivative (2-12). Method for green route of synthesis of CdS QD in [BMIM]Cl was established in our lab. Quantum dots (CdSe and CdS) were characterized by the TEM, DLS, UV-Vis, and Fluorescence. Calix[4]arene derivatives (1-12) were synthesized and characterized by FTIR and 1H NMR spectroscopy. Calix[4]arene derivatives adsorption on CdSe QD1-4 was characterized by fluorescence quenching and the binding characteristics were studied by applying Stern-Volmer plot to Langmuir adsorption. A non-covalent interaction between 2-12 and TOPO capped CdSe QD1-4 was observed. CdSe QD and Calix[4]arene derivative capped CdS QDs were evaluated for fluorescence sensing behavior towards sixteen polynuclear aromatic hydrocarbons (PAHs) and aromatic analytes, respectively. 2atQD2, 4atQD2, 7atQD2 and 9atQD2 showed selective and sensitive fluorescence enhancement in upto presence of fluorine (8 nM), acenaphthelene (30 nM), acenaphthene (135 nM) and benzo[b]fluorenthene (15 nM), respectively. However, 2atCdS QDs Showed selective and sensitive fluorescence enhancement in benzene. The limit of detection for benzene using 2atCdS QDs was found to be upto 30 nM. The proposed method was demonstrated for its use in determination of fluorene, acenaphthelene, acenaphthene and benzo[b]fluorenthene in spiked respirable dust (PM10) in ambient air samples collected during the open biomass (stubble) burning event in Bathinda, Punjab, ground water, milli Q water and canal water from CUP, Bathinda.