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 x 10(-6)-1.0 x 10(-4) mol L-1 and the detection limit was 5.0 x 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. (C) 2014 Elsevier B.V. All rights reserved.