Sensitive detection of dopamine and quinone drugs based on the quenching of the fluorescence of carbon dots

In this work, we demonstrated that the quinone structure can quench the fluorescence of the carbon dots （CDs）. The sensitive determination of dopamine （DA） was studied primarily based on this principle. DA would be transformed into DA quinone under alkaline conditions, which resulted in fluorescence quenching of the CDs. A good linear range from 5 nmol/L to 0.4 mmol/L was obtained and the detection limit was 1 nmol/L. Moreover, the quenching effect of quinone structure on the fluores- cence of CDs was confirmed by Fourier transform infrared spectra, time-correlated single-photon counting and X-ray photoelectron spectroscopy. Remarkably, CDs were firstly applied to detect the quinone drugs quantitatively which contained typical quinone structure based on the quenching mechanism. More than this, the sensing platform was demonstrated to provide credible selectivity and satisfac- tory stability in human serum solution with good linerrange. Hence, our practical application and mechanism have showed great potential for diagnostic purposes.