Boronic acid functionalized nitrogen doped carbon dots for fluorescent turn-on detection of dopamine

The authors describe blue-green emitting nitrogen doped carbon dots (NCDs) synthesized through a microwave assisted polyol method and by using lactose as the carbon source, ammonium chloride as nitrogen source and PEG 200 as the reaction medium. The surfaces of the NCDs is rich in carboxy groups and can be functionalized with aminophenylboronic acid (APBA) to obtain APBA-modified carbon dots which are shown to a viable fluorescent probe for dopamine (DA). Operated best at excitation wavelength of 370 nm, the fluorescence of the probe increases with increasing concentration of DA. The detection limit is as low as 89 pM. The probe has good selectivity for DA over other interfering neurotransmitters, saccharides, amino acids and antioxidants. It was successfully employed for the detection of DA in (spiked) human serum samples and gave good recoveries.