A Comprehensive Review of Caffeine and Nicotine as Emerging Environmental Contaminants in Water Systems

The increasing presence of persistent toxins from natural pollutants, such as caffeine and nicotine, has raised significant environmental concerns. These compounds, widely used in consumer products, are frequently detected in surface water and wastewater treatment plants, where they pose ecological risks and potential threats to human health due to bioaccumulation. Given their extensive presence, caffeine and nicotine serve as effective biomarkers for tracking pollutant dispersion and environmental contamination. This review provides a comprehensive analysis of the advanced analytical techniques employed for the detection and quantification of caffeine and nicotine in environmental matrices. Various sampling strategies, including composite and grab sampling, are examined for their effectiveness in capturing pollutant concentrations over time. Sample preparation methodologies, such as solid-phase extraction and chemical extraction, play a crucial role in isolating target compounds for precise analysis. The review further explores instrumental techniques, with liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry emerging as the gold standards due to their high sensitivity and specificity. High-performance liquid chromatography is widely utilized for its precision in separating complex mixtures. Additionally, microscopic techniques, including scanning electron microscopy and transmission electron microscopy, provide valuable insights into the structural and morphological characteristics of pollutants at the microscopic level.By critically evaluating the strengths and limitations of these methods, this review underscores the challenges in monitoring caffeine and nicotine as emerging contaminants. The insights presented aim to improve environmental pollution assessment frameworks and support the development of effective remediation strategies for safeguarding aquatic ecosystems and public health.