A highly selective fluorescent enhancement sensor for Al3+ based nitrogen-doped carbon dots catalyzed by Fe3+

Abstract

A new fluorescent material based nitrogen-doped carbon dots (N-CDs) was proposed for fabrication of selective turn-on fluorescent sensor for detection of Al3+. The N-CDs were facile synthesized by using sucrose and urea in the presence of Fe3+ as catalyst. The reaction was facile carried out in hot diluted sulfuric acid within only 20 min. The as-prepared N-doped carbon dots (N-CDs) exhibited good fluorescent emission, large stroke shift (λex = 311 nm, λem = 428 nm), spherical shape and narrow size distribution with the particle size around 3.9 ± 1.2 nm. The N-CDs exhibited excellence selectivity towards the detection of Al3+. In the presence of Al3+ at trace level, the un-expected fluorescent enhancement was observed while other metal ions did not alter the fluorescent signal. Enhancement of the fluorescent intensity of the N-CDs linearly increased with the increasing of the Al3+ concentration in the concentration range of 0.1–5.5 μM with the lowest detection limit of 9.7 nM. The proposed sensor was applied to determine Al3+ in real sample including water samples and bean grain with satisfactory results.