Size-dependent electrochemiluminescence behavior of water-soluble CdTe quantum dots and selective sensing of L-cysteine

Water-soluble CdTe quantum dots (QDs) with five sizes (2.25, 2.50, 2.77, 3.12, and 3.26 nm) were synthesized with the hydrothermal method. The electrochemiluminescence (ECL) of CdTe QDs was investigated in detail in air-saturated solution without adding foreign oxidant. It Was found that the ECL of CdTe QDs displayed a size-dependent property. With the increasing in the particle size of the CdTe QDs, the ECL intensity was gradually increased, in addition, both ECL peak potentials and ECL onset potentials of CdTe QDs were shifted positively. Influences of some factors on the ECL intensity were investigated. Under the optimal conditions, the ECL intensity had a linear relationship with the concentration of L-cysteine (L-CYS) in the range from 1.3 x 10(-6) to 3.5 x 10(-5) mol L-1 (R-2 0.996) with a detection limit of 8.7 x 10(-1) mol L-1 (S/N = 3). The proposed method was applied to the determination of L-CYS in real samples with satisfactory results. Compared with previous reports, it has better selectivity for the determination of L-CyS. (C) 2008 Elsevier B.V. All rights reserved.

采用水热法合成了5种尺寸（2.25、2.50、2.77、3.12和3.26 nm）的水溶性碲化镉量子点（QDs）。在不添加外来氧化剂的空气饱和溶液中详细研究了碲化镉量子点的电化学发光（ECL）。发现碲化镉量子点的电化学发光呈现出尺寸依赖性。随着碲化镉量子点粒径的增大，电化学发光强度逐渐增强，此外，碲化镉量子点的电化学发光峰电位和起始电位均正向移动。研究了一些因素对电化学发光强度的影响。在最佳条件下，电化学发光强度与L - 半胱氨酸（L - CYS）浓度在1.3×10⁻⁶到3.5×10⁻⁵ mol/L范围内呈线性关系（R² = 0.996），检测限为8.7×10⁻⁷ mol/L（S/N = 3）。将所提出的方法应用于实际样品中L - CYS的测定，结果令人满意。与先前的报道相比，它对L - CYS的测定具有更好的选择性。（C）2008爱思唯尔有限公司。保留所有权利。