Poly(carbazole-co-1,4-dimethoxybenzene): Synthesis, Electrochemiluminescence Performance, and Application in Detection of Fe(3+)

In this study, four polycarbazole derivatives (PCMB-Ds) with different alkyl side chains were designed and synthesized via Wittig–Horner reaction. A novel solid-phase electrochemiluminescence (ECL) system was prepared by immobilizing PCMB-D on an indium tin oxide (ITO) electrode with polyvinylidene fluoride (PVDF) in the presence of tripropylamine (TPrA). It could be found that the increase in alkyl side chain length had little effect on the ECL signal of PCMB-D, while the increase in the degree of polymerization (DP) greatly enhanced the ECL signal. Furthermore, the P-3/ITO ECL sensor based on the polyoctylcarbazole derivative (P-3) with the best ECL performance was successfully constructed and detected Fe(3+) under the optimal experimental conditions. The ECL signal steadily diminished with the increased concentration of Fe(3+) because of the competition and complexation between Fe(3+) and P-3 under the condition of pH 7.4. This P-3/ITO platform could realize a highly sensitive and selective detection of Fe(3+) with a wide detection range (from 6 × 10(−8) mol/L to 1 × 10(−5) mol/L) and low detection limit of 2 × 10(−8) mol/L, which could allow the detection of Fe(3+) in multiple scenarios, and would have a great application prospect.