Dopamine functionalized–CdTe quantum dots as fluorescence probes for l-histidine detection in biological fluids

In this paper, we developed dopamine functionalized–CdTe quantum dots as fluorescence probes for the determination of l-histidine. Firstly, CdTe was covalently linked to dopamine to form a kind of fluorescence sensor with pyrocatechol structure on the surface. The photoluminescence intensity of CdTe–dopamine (QDs–DA) could be quenched by Ni2+ due to the strong coordination interaction between the pyrocatechol structure of QDs–DA and Ni2+. In the presence of l-histidine, Ni2+ preferred to bind with l-histidine due to high affinity of Ni2+ to l-histidine and the photoluminescence intensity of QDs–DA was recovered. The recovered photoluminescence intensity of QDs–DA was proportional to the concentration of l-histidine in the ranges of 1.0×10−6–1.0×10−4 mol L−1 and the detection limit was 5.0×10−7 mol L−1 respectively. The established method showed a good selectivity for l-histidine among other common amino acids, and it was applied for determination of l-histidine in human serum sample with satisfactory results.