BACKGROUND AND OBJECTIVES: The need for sustainable, rapid, and cost-effective electrochemical sensors for formaldehyde monitoring is increasing. Traditional noble metal nanoparticle synthesis often uses hazardous chemicals. This study pioneered the green synthesis of gold nanoparticles using Nypa fruticans leaf extract. The core objectives of the study were to develop a highly sensitive and selective electrochemical formaldehyde sensor by integrating these novel, green-synthesized gold nanoparticles into a conductive fish albumin composite matrix on a gold electrode.METHODS: Gold nanoparticles were created using a simple heating and stirring method with Nypa fruticans leaf extract, utilizing its natural metabolites. Formation was confirmed using ultraviolet-visible, fourier transform infrared, x-ray diffractometer, Particle size analyzer, field emission-scanning electron microscope, and High-resolution transmission electron microscopy analyses. The sensor probe, incorporating the gold nanoparticles into a snakehead fish albumin-paraffin composite, was fabricated and applied to a gold wire electrode. Its electrochemical performance was evaluated Electrochemical sensor; Fish albumin; Formaldehyde detection; Green synthesis; Gold nanoparticles (AuNps).against a 1 millimolar formaldehyde solution using cyclic voltammetry. Key parameters, including optimal potential of hydrogen, reaction kinetics, linear dynamic range, limit of detection, and selectivity against common interferents (methanol, ethanol, glucose, glycerol), were investigated.FINDINGS: Characterization confirmed the successful formation of crystalline, face-centered cubic gold nanoparticles, predominantly spherical, with small sizes ranging from 2 to 8 nanometers, highlighting the efficacy of the green synthesis method. The gold electrode modified fish albumin and gold nano particles exhibited significantly enhanced anodic peak current at +1.13 volt compared to control electrodes (Paraffin-modified gold electrodes and fish albumin-modified gold electrodes), demonstrating the superior catalytic and conductive properties imparted by the gold nanoparticles. Optimal sensing performance was achieved under acidic conditions with a pH value of 1. The electrode displayed a broad linear dynamic range from 1 micromolar to 50 millimolar. Critically, the sensor has good sensitivity and selectivity with an ultra-low limit of detection of 0.177 micromolar, the lowest reported among the compared electrodes in the literature, especially the albumin-modified gold electrode, which has a detection limit of 4.07 micromolar for formaldehyde.CONCLUSION: Environmentally friendly synthesis of gold nanoparticles uses Nypa fruticans extract, providing a sustainable, cost-effective method. The resulting gold electrode, modified with fish albumin and gold nanoparticles, created an electrochemical sensor with exceptional performance, high selectivity, and an ultralow detection limit for formaldehyde detection.
Hutapea et al. (2026) studied this question.