title: A "Turn-On" thiol functionalized fluorescent carbon quantum dot based chemosensory system for arsenite detection.
abstract: Carbon quantum dots (CQDs) have emerged out as promising fluorescent probes for hazardous heavy metals detection in recent past. In this study, water soluble CQDs were synthesized by facile microwave pyrolysis of citric acid & cysteamine, and functionalized with ditheritheritol to impart thiol functionalities at surface for selective detection of toxic arsenite in water. Microscopic analysis reveals that the synthesized CQDs are of uniform size (diameter ∼5nm) and confirmed to have surface SH groups by FT-IR. The functionalized probe is then demonstrated for arsenite detection in water by "Turn-On" read out mechanism, which reduces the possibility of false positive signals associated with "turn off' probes reported earlier. The blue luminescent functionalized CQDs exhibit increase in fluorescence intensity on arsenite addition in 5-100ppb wide detection range. The probe can be used for sensitive detection of arsenite in environmental water to a theoretical detection limit (3s) of 0.086ppb (R2=0.9547) with good reproducibility at 2.6% relative standard deviation. The presented reliable, sensitive, rapid fCQDs probe demonstrated to exhibit high selectivity towards arsenite and exemplified for real water samples as well. The analytical performance of the presented probe is comparable to existing organic & semiconductor based optical probes.
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research, New Delhi, India; Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India. Electronic address: poojaiitr@csio.res.in.
authors.forename: Pooja
authors.initials: P
authors.lastname: D
authors.affiliation: Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India.
authors.forename: Sonia
authors.initials: S
authors.lastname: Saini
authors.affiliation: Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India.
authors.forename: Anupma
authors.initials: A
authors.lastname: Thakur
authors.affiliation: Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India.
authors.forename: Baban
authors.initials: B
authors.lastname: Kumar
authors.affiliation: Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India.
authors.forename: Sachin
authors.initials: S
authors.lastname: Tyagi
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research, New Delhi, India; Central Scientific Instruments Organisation, Sectro-30 C, Chandigarh 160030, India.
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Nayak
keywords: Arsenite; Carbon quantum dots; Fluorescence; Turn–On