Fabrication of dual emission carbon dots and its use in highly sensitive thioamide detection

Abstract Highly sensitive thioamide sensor was realized by the fluorescent carbon dots (CDs) synthesized using l -tryptophan and ethylenediaminetetraacetic acid as novel precursors via hydrothermal synthesis. The as-synthesized CDs exhibit dual emission bands at 360 and 450 nm, which corresponded to the tryptophanyl cores, and defects and/or functional group related emission sites. The reaction conditions including reaction time, temperature, and the precursor ratio were systematically studied to obtain the high quantum yield and quenching efficiency. This is the first report to use organic CDs in thioacetamide (TAA) detection. Although workers in leather, textile, paper industries suffer from exposure of TAA well-known as liver carcinogen to human, there was no method which facilitate non-toxic, simple and rapid detection. When the as-synthesized CDs were used as thioacetamide (TAA) sensing, an extremely low detection limit (~70 nM) and a very wide linear range (0–10 mM) were achieved by the different TAA induced quenching properties of each emission band. Moreover, their properties were much better than those of amperometry or voltammetry based TAA sensing.