Structuring biogenic synthesis of rare phase LaMn2O5 using the Bauhinia variegata (Kachnar) flower extract for highly sensitive, long range electrochemical detection of bisphenol-A, an endocrine disruptor

Abstract

This work presents the in situ biogenic synthesis of rare phase nanostructure LaMn₂O₅ by the hydrothermal method, using the Bauhinia variegata (Kachnar) extract to prevent the discharge of hazardous and toxic waste elements into the environment. In this study, the compound exhibits strong Mn-3p and O-2p interactions, closely associated with vacant La-4f orbitals resulting in strong covalent bonding. Moreover, the synergetic effect of the f–d block metals effectively facilitates electron transfer. In this work, biologically derived, rare phase LaMn₂O₅ was also fabricated as a bioelectrode and developed into an electrochemical sensor. The estimated biosensor was assessed across a wide range of analyte concentrations for detecting the plastic monomer and endocrine disruptor bisphenol-A (BPA). A three-step linear response was observed, spanning from 0.001 μM to 0.1 μM, 1.0 μM to 40 μM and 40 μM to 1000.0 μM with a limit of detection (LOD) value of 2.85 × 10⁻³ μM and negligible interference. The sensitivity was obtained to be 3.67 mA μM⁻¹ cm⁻². Cyclic voltammetry (CV), pH, and scan rate studies were also performed for the prepared nanomaterials. From the scan rate study, the diffusion coefficient (D), charge transfer rate (K_s), and surface concentration (γ) were calculated which were found to be appreciable. The synthesized rare phase nanostructure LaMn₂O₅ exhibited a response time of 30 seconds, 60 days long stability, and 13 times reusability. This study reveals the biogenic synthesis of rare phase nanostructure LaMn₂O₅. This innovative method has the potential to harness natural resources for the synthesis of distinct nanomaterials. The rare phase nanostructure LaMn₂O₅ appears to be highly susceptible, in the long-range detection of BPA.