INNOVATIONS IN ENVIRONMENTAL ANALYTICAL CHEMISTRY: TRANSITION FROM CONVENTIONAL TECHNIQUES TO NANO-ENABLED SENSING TECHNOLOGIES

Ezekiel Izudike Odimgbe, Micheal Abimbola Oladosu*, Moses Adondua Abah, Joseph Ezeani, Alaba Oladapo Gbadebo, Chigozirim Steve Amadi

ABSTRACT

Environmental contamination from heavy metals, pesticides, pharmaceutical residues, per- and polyfluoroalkyl substances (PFAS), and microplastics poses grave risks to human health and ecosystems. Classical analytical methods, including flame atomic absorption spectrometry (FAAS), gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC), offer high accuracy but are constrained by high cost, laboratory dependence, lengthy sample preparation, and limited real-time capability. The emergence of nanotechnology has revolutionised environmental analytical chemistry by enabling sensors with detection limits several orders of magnitude below regulatory thresholds, rapid response times, and field-deployable formats. This review critically examines the transition from conventional environmental monitoring platforms to nano-enabled sensing technologies, with emphasis on gold nanoparticles, carbon nanotubes, graphene and its derivatives, quantum dots, metal-organic frameworks (MOFs), and molecularly imprinted nanoparticles. Electrochemical, optical, and surface-enhanced Raman scattering (SERS) transduction principles are discussed, with a comparison of analytical performance metrics from peer-reviewed studies published between 2020 and 2025. Challenges, including nanomaterial stability, matrix interferences, regulatory acceptance, and environmental safety of the sensors themselves, are critically evaluated. Future directions towards integrated lab-on-chip platforms, artificial intelligence-assisted signal processing, and wearable environmental monitors are highlighted. The review concludes that nano-enabled sensing technologies are poised to become the gold standard for real-time, on-site environmental quality assessment.

Keywords: environmental analytical chemistry; nanosensors; heavy metals; electrochemical biosensors; graphene; quantum dots; SERS; PFAS; nanomaterials; water quality monitoring.