Carbon dots (CDs), represented as an exciting new class of oxygen-containing carbonic emitters since their inspective discovery in 2004, have inspired multiple investigations as sensing platform in a wide range of applications regarding to their fascinating optical and fluorescence properties. Contrary to the low toxicity and high biocompatibility of carbon dots, other carbonaceous nanomaterials such as carbon nanotubes (CNTs) that are extensively used in electronics and batteries with a production of thousands of tons per year are known to be the new oncoming nano-contaminant due to their high toxicity to living organisms. Herein, we described a simple and low-cost sensing method to detect and quantify carboxylated multiwalled CNTs that are produced from the industry pollution and diesel combustion and accumulated in river water.
Low-cost fluorescent carbon dots were created from the most abundant polymer on Earth, cellulose, via acid thermal hydrolysis by one-pot reaction without the need of any further passivation or functionalization reactions.
The detection of c-MWCNTs is based on the fluorescence quenching of carbon dots owing to the formation of hydrogen bond interactions between the oxygen-containing groups of both types of nanoparticles. Quenching mechanism is assumed from variable-temperature fluorescence measurements. The detection and quantification limits were 0.37 and 1.25 g mL−1, respectively, and the relative standard deviation was 0.83%.
Thus, other carbonaceous materials such as single-walled carbon nanotubes (SWCNTs), graphene-based products and even humic acids (HA) were evaluated as potential interferences. Contrary to carboxylated MWCNTs, none of the carbonaceous selected interferences did quench significantly the PL of carbon dots. The validation was performed in spiked samples for Guadalquivir River.
Sensors and Actuators B: Chemical, Volume 207, Part A, 2015, P 596-601. Angelina Cayuela, M. Laura Soriano, Miguel Valcárcel.
Department of Analytical Chemistry, Marie Curie Building. Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
Inexpensive bright photoluminescence carbon dots (CDs) generated from the “bottom-up” procedure using cellulose as carbon source have proven to be a potential fluorescent platform for sensing multiwalled carbon nanotubes (MWCNTs) accumulated in river water after industrial discharges by a simple, rapid and efficient luminescent method.