Sensing of bisphenol A and mercury ions in aqueous solutions using a functionalized porous gold electrode

• A porous gold electrode pellet was prepared by templating and simple pressing.
• The prepared porous gold had high surface area and electrical conductivity.
• Target analytes were analyzed via an indirect ferricyanide oxidation reaction.
• Measurement of the electrode current was highly correlated with analyte concentrations.
• BPA-sensing-electrode could be reused several times by simple solvent washing.

Endocrine disrupting compounds (EDCs) such as bisphenol A (BPA) and mercury ions can accumulate in living tissue, causing many health problems. Therefore, to prevent contaminated water and products reaching consumers, it is necessary to develop a sensitive and efficient sensing system for these compounds. However, common analytical techniques for EDCs are based on mass spectrometry, which is both costly and requires an expert analyst. Herein, we describe the preparation of a functionalized, porous gold electrode for electrochemical sensing of BPA and mercury ions in aqueous solutions that is formed via a templating method and simple pressing. The prepared porous gold electrode was characterized by SEM-EDS, N2 adsorption-desorptions, and FTIR spectroscopy. The prepared porous gold has a very large surface area (8.1 m2/g) and comparable electrical conductivity (1.33 × 104 S/cm) to pure gold. To prevent electrode poisoning by oxidation byproducts of the target analytes, an indirect sensing method was used: the ferricyanide oxidation reaction. For hexyl and thiol-functionalized porous gold electrodes (C6–PAu and SH-PAu), a linear relationship between the current responses and the concentrations of BPA and mercury ions with high correlation coefficients (≥0.9998) at very low aqueous concentrations (≤0.7 μM) was found using differential pulse voltammetry measurements. Also, the C6–PAu electrode could be regenerated easily by washing with ethanol, and was reused five times consecutively.

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