Macromolecular Systems with MSA-Capped CdTe and CdTe/ZnS Core/Shell Quantum Dots as Superselective and Ultrasensitive Optical Sensors for Picric Acid Explosive.
This work reports the development of highly fluorescent materials for the selective and efficient detection of picric acid explosive in the nanomolar range by fluorescence quenching phenomenon. Poly(vinyl alcohol) grafted polyaniline (PPA) and its nanocomposites with 2-mercaptosuccinic acid (MSA)-capped CdTe quantum dots (PPA-Q) and with MSA-capped CdTe/ZnS core/shell quantum dots (PPA-CSQ) are synthesized in a single step free radical polymerization reaction. The thermal stability and photo stability of the polymer increases in the order of PPA < PPA-Q < PPA-CSQ. The polymers show remarkably high selectivity and efficient sensitivity toward picric acid, and the quenching efficiency for PPA-CSQ reaches up to 99%. The detection limits of PPA, PPA-Q, and PPA-CSQ for picric acid are found to be 23, 1.6, and 0.65 nM, respectively, which are remarkably low. The mechanism operating in the quenching phenomenon is proposed to be a combination of a strong inner filter effect and ground state electrostatic interaction between the polymers and picric acid. A portable and cost-effective electronic device for the visual detection of picric acid by the sensory system is successfully fabricated. The device is further employed for quantitative detection of picric acid in real water samples.
Advanced Materials Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology , Guwahati 781 035, India.
Priyanka
P
Dutta
Plasma Section, Physical Sciences Division, Institute of Advanced Study in Science and Technology , Guwahati 781035, India.
Dilip
D
Saikia
Plasma Section, Physical Sciences Division, Institute of Advanced Study in Science and Technology , Guwahati 781035, India.
Nirab Chandra
NC
Adhikary
Advanced Materials Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology , Guwahati 781 035, India.
Neelotpal Sen
NS
Sarma
core/shell quantum dots; fluorescence quenching; picric acid sensing; polymer nanocomposites; quantum dots