TPyP-sPEEK composite membranes are developed and deposited onto commercial screen-printed electrodes for the electrochemical detection of Pb²⁺, Cd²⁺, and Hg²⁺ in water. Optimal performance is achieved with 5% porphyrin loading, enabling low detection limits, excellent stability, and reproducibility. The sensor utilizes synergistic interactions between porphyrin and sulfonated polymer, providing a promising approach for environmental monitoring.

Porphyrin/sulphonated polyetheretherketone (sPEEK) composites are successfully obtained at different dye/polymer weight/weight percentage taking advantage of electrostatic interactions among the protonable nitrogen atoms of 5,10,15,20-tetrakis(4-pyridyl)-21H,23H-porphyrin porphyrin (TPyP) and anionic sulphonated groups of the polymer with 65% of sulfonation degree. These supramolecular adducts(TPyP-sPEEK) are drop-casted onto a commercial screen-printed carbon substrate (SPCE) to fabricate new modified TPyP-sPEEK /SPCE sensors for the detection of heavy metal ions such as Pb²⁺, Cd²⁺, and Hg²⁺. Sample at different porphyrin loads has been analyzed by electrochemical techniques. sPEEK composite with 5% porphyrin/polymer w/w% is identified as the optimal one in terms of stability and high percentages of recovery of the tested heavy metal ions in seawater environment.