Naked-eye colorimetric analysis of Hg²⁺ with bi-color CdTe quantum dots multilayer films
2011
Yang, Fengping | Ma, Qiang | Yu, Wei | Su, Xingguang
A novel direct quantificational method through naked-eye colorimetric analysis of Hg²⁺ was constructed based on different degree of the fluorescence quenching of bi-color quantum dots (QDs) multilayer films (2-QDMF). The functional multilayer films were assembled by layer-by-layer (LBL) deposition of oppositely charged CdTe QDs and poly(dimethyldiallylemmonium chloride) (PDDA). Then the outermost layer of 2-QDMF was cross-linked to bovine serum albumin (BSA), polyethylene glycol (PEG) or glutathione (GSH). It was found that when BSA modified quartz slides were immersed into solutions containing Hg²⁺ and Cu²⁺ respectively, the 2-QDMF can be quenched by Hg²⁺, but not by Cu²⁺. Under the optimization conditions, the quenched photoluminescence (PL) intensities of multilayer films were almost linearly proportional to the concentration of Hg²⁺ in the range of 1.0×10⁻⁸ to 1.0×10⁻⁶molL⁻¹ and the detection limit was 4.5×10⁻⁹molL⁻¹. The proposed method is intuitional and convenient, which can be applied to the determination of trace Hg²⁺ in the artificial water sample with satisfactory results.
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