Dimeric phthalocyanine-involved double-decker complex-based electrochemical sensor for simultaneous detection of acetaminophen and ascorbic acid

An electrochemical sensor for simultaneous detection of acetaminophen (APAP) and ascorbic acid (AA) is firstly developed by using the self-assembled film of a novel dimeric bis(phthalocyaninato) europium complex, [{Pc(SC₂H₅)₈}Eu{BiPc(SC₂H₅)₁₂}Eu{Pc(SC₂H₅)₈}] (1) coated onto ITO (fim-1/ITO) fabricated through a solution-processing quasi-Langmuir­Shäfer (QLS) protocol. A combination of unique sandwich molecular structure with extented π-conjugated system and J-type aggregates with quite uniform nanograins (ca. 15 nm) formed on ITO substrate render the film of 1 the excellent charge transfer ability and abundant electroactive sites, resulting in sensitive detection of APAP and AA with the good sensitivities of 254 and 85.6 mA µM⁻¹ cm⁻² and low detection limits of 1.3 and 3.7 µM for APAP and AA respectively. More importantly, a simultaneous determination of APAP and AA at a coexisting system of APAP and AA is also achieved with the still good sensitivities of 317 and 64.7 mA µM⁻¹ cm⁻², and low detection limits of 1.0 and 4.9 µM for APAP and AA respectively. This work represents the first example of tetrapyrrole-based organic semiconductor electrochemical sensor for simultaneous detection of APAP and AA with excellent sensing performance, implying the great application potential of electroactive sandwich rare earth tetrapyrrole compounds in the nonenzymatic electrochemical sensors.