1：Experimental Design and Method Selection

The study involved the synthesis of a novel tetraazo-bridged cobalt phthalocyanine polymer and its characterization using various techniques. The polymer was then mixed with carbon nanoparticles to modify a glassy carbon electrode for nitrite sensing.

2：Sample Selection and Data Sources

The samples used included the synthesized polymeric phthalocyanine and carbon nanoparticles. Data was sourced from elemental analysis, UV-Vis, FTIR, TGA, XRD, and electrochemical measurements.

3：List of Experimental Equipment and Materials

Equipment included a Perkin-Elmer model lambda 35 spectrophotometer, Perkin-Elmer FT-IR spectrometer, STA6000 machine for TGA, Bruker D8 Advance X-ray diffraction machine, and CHI6005E electrochemical analyser. Materials included phthalic anhydride, 4-Nitrophthalonitrile, ammonium molybdate, urea, CoCl2, and others.

4：Experimental Procedures and Operational Workflow

The synthesis involved diazotization of p-phenylenediamine and coupling with 2-naphthol, followed by nucleophilic aromatic nitro displacement and polycyclotetramerization. The modified electrode was prepared by drop casting the polymer and CNP mixture onto a glassy carbon electrode.

5：Data Analysis Methods

Data analysis involved interpreting UV-Vis, FTIR, TGA, XRD spectra, and electrochemical measurements to characterize the polymer and evaluate its sensing performance.