Simultaneous electrochemical sensing of thallium, lead and mercury using a novel ionic liquid/graphene modified electrode

• A sensor using ionic liquid, graphene and phosphorus ylide was constructed.
• The surface morphology and properties of the electrode characterized.
• Simultaneous determination of Tl+, Pb2+ and Hg2+ in real samples was investigated.
• It is a useful method for determining of these analytes without overlapping problem.
• In comparison to previous methods, this method has wonderful figures of merit.

In the present manuscript, an electrochemical sensor for the sensitive detection of Tl+, Pb2+ and Hg2+ is described. A new composite electrode has been fabricated using graphene, 1-n-octylpyridinum hexafluorophosphate (OPFP), and [2,4-Cl2C6H3C(O)CHPPh3] (L), as a new synthetic phosphorus ylide. The physicochemical and electrochemical characterizations of fabricated sensor were investigated in details. The advantages of the proposed composite electrode are its ability in simultaneous electrochemical detection of Tl+, Pb2+ and Hg2+ with good selectivity, stability and no need for separating of the three species from complex mixtures prior to electrochemical measurements. The analytical performance of the proposed electrode was examined using square wave voltammetry. Tl+, Pb2+ and Hg2+ can be determined in linear ranges from 1.25 × 10−9 to 2.00 × 10−7 mol L−1. Low detection limits of 3.57 × 10−10 mol L−1 for Tl+, 4.50 × 10−10 mol L−1 for Pb2+ and 3.86 × 10−10 mol L−1 for Hg2+ were achieved. Finally, the proposed electrochemical sensor was applied to detect trace analyte ions in various water and soil samples with satisfactory results.

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