Chitosan Film Containing an Iron Complex: Synthesis and Prospects for Heterocyclic Aromatic Amines (HAAs) Recognition

Hybrid organic-inorganic materials have been seen as a promising approach to produce sensors for the detection and/or recognition of heterocyclic aromatic amines (HAAs). This work shows the synthesis of a hybrid film as a result of the incorporation of [Fe(CN)₅(NH₃)]^3- into chitosan (CS); CS-[(CN)₅Fe(NH₃)]^3-. The sensitivity of CS-[(CN)₅Fe(NH₃)]^3- toward HAA-like species was evaluated by using pyrazine (pz) as probe molecule in vapor phase by means of electrochemistry and spectroscopic techniques. The crystallinity (SEM-EDS and XRD) decrease of CS-[(CN)₅Fe(NH₃)]^3- in comparison to CS was assigned to the disturbance of the hydrogen bond network within the polymer. Such conclusion was reinforced by the water contact angle measurements. The results presented in this work indicate physical and intermolecular interactions, mostly hydrogen bond, between [Fe(CN)₅(NH₃)]^3- and CS, where the complex is likely trapped in the polymer with its sixth coordination site available for substitution reactions.