Flower-Like SrMoO4 integrated f-CNF nanohybrid as an electrocatalyst for the detection of N-Substituted amines in environmental and food samples: Combined experimental and DFT insights

• A SrMoO 4 /f-CNFs-based sensor was successfully fabricated for DPA detection. • The sensor showed a wide linear range with low detection limit and good selectivity. • The SrMoO 4 /f-CNFs/GCE exhibited good repeatability, reproducibility, and stability. • DFT calculations revealed energy levels and electron transfer sites of DPA. • Sensor applicability was validated in food and water samples with good recovery. Diphenylamine (DPA) is widely employed as an anti-scald agent for post-harvest fruit preservation. Despite its effectiveness, excessive DPA residues pose serious concerns due to their potential to contaminate water sources via agricultural runoff, leading to environmental pollution and health risks. Therefore, the development of reliable and sensitive methods for DPA detection is essential for ensuring food safety and environmental protection. In this study, an advanced electrochemical sensor was developed by modifying a glassy carbon electrode (GCE) with a nanocomposite consisting of strontium molybdate (SrMoO 4 ) and functionalized carbon nanofibers (f-CNFs). The synergistic interaction between SrMoO 4 and f-CNFs significantly enhanced the electrocatalytic activity and conductivity of the sensor. The fabrication strategy aimed to exploit these properties to achieve high sensitivity and selectivity in DPA detection. The fabricated SrMoO 4 /f-CNF-modified GCE sensor demonstrated excellent analytical performance, including high sensitivity (0.46 μA μM -1 cm -2 ), a low detection limit (2.09 nM), a wide linear range (0.005 to 1381.5 μM), and strong selectivity, stability, and reproducibility, with successful detection of DPA in spiked food and environmental samples yielding recovery rates of 94–99 %, confirming its suitability for real-time monitoring in food safety and environmental applications.