Interaction of tetracycline with l-cysteine functionalized CdS quantum dots - Fundamentals and sensing application.

The present paper reports l-cysteine functionalized CdS quantum dots (QDs) as a simple and highly selective turn-off fluorescence sensor for the determination of tetracycline (TET). The unauthorized use of TET may pose serious health hazards in human beings and hence the detection and determination has become very essential. In this regard, we have developed a sensor that enable the quantification of TET in the range 6.00 × 10-4 M to 1.50 × 10-5 M with a limit of detection 7.78 × 10-6 M, under optimized conditions. Steady state and time resolved fluorescence spectroscopic studies were used for investigating the mechanism of quenching and was found to be a combination of static and dynamic processes. The analytical application of the proposed sensor was investigated in pharmaceutical formulation.