A chemiluminescence method for the determination of mercury(ii) ions by tuning the catalytic activity of gold nanoparticles with ethylenediamine

Abstract

The development of simple and sensitive detection methods for mercury(II) ions (Hg²⁺) is crucial for environmental monitoring and human health protection. In the present study, ethylenediamine was found to inhibit the catalytic activity of gold nanoparticles (Au NPs) in the luminol–AgNO₃ chemiluminescence (CL) reaction. Interestingly, the specific binding of Hg²⁺ to the amino groups of ethylenediamine leads to the recovery of the CL signal. Hence, a simple and ultrasensitive CL detection method for the quantitative detection of Hg²⁺ was developed. In principle, the CL signal of the luminol–AgNO₃–Au NPs CL reaction is quenched by ethylenediamine in the absence of Hg²⁺. On the contrary, with the addition of Hg²⁺ to the reaction system, the specific binding of Hg²⁺ to the amino groups of ethylenediamine leads to an enhanced CL intensity. Accordingly, the concentration of Hg²⁺ in the aqueous solution can be quantitatively detected. Under optimal conditions, the linear range for the detection of Hg²⁺ was from 1 fM to 1 pM with a detection limit of 0.54 fM. Also, the developed CL sensing method exhibited a high selectivity toward Hg²⁺ over other metal ions. This cost-effective and ultrasensitive sensing method was applied to determine Hg²⁺ in tap water samples with satisfactory recoveries.