A sensitive method for the detection of catecholamine based on fluorescence quenching of CdSe nanocrystals.

A sensitive method for the detection of catecholamine based on the fluorescence quenching of CdSe nanocrystals was developed. The sodium citrate-protected CdSe nanocrystals were synthesized in water solution. The fluorescence quenching of CdSe nanocrystals by dopamine, uric acid, ascorbic acid and catechol was studied; the results showed that all of these four kinds of compounds could quench the fluorescence of nanocrystals, and the quenching constant was 6.3x10(4), 2.57x10(3), 2.14x10(3) and 1.168x10(3), respectively. The order of sensitivity for the biosensor was: dopamine>lactic acid>ascorbic acid>catechol. This method shows good selectivity for dopamine, the detection limit reaches 5.8x10(-8)M.