Meyliana Wulandari, Muhammad Al Faqih Fiddin, Dieta Putri Ayuserani, Rosi Fitri Ramadani, Syabina Khaila Aliffa, Nofrizal, Andreas, Pandian Bothi Raja, Thomas Nesakumar Jebakumar Immanuel Edison
Formalin (aqueous formaldehyde) is a well-documented human carcinogen often used as an illegal food preservative. The World Health Organization (WHO) limits the daily intake of formalin to 1.5–14 mg for adults. Higher dosages of formalin can cause death by throat swelling or lung burning. Hence, the need for an instant, selective, and sensitive method for detecting formalin is clear. The present work discusses the efficient synthesis of silica-supported molecularly imprinted polymers (SiO2@MIPs) for the selective and sensitive detection of formalin using a UV-visible spectrophotometer. This method offers rapid detection with high specificity and sensitivity, enabling timely detection of formalin in food matrices. The synthesized SiO2@MIPs are characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and a particle size analyzer (PSA). After reaction with SiO2@MIPs, formalin reacted colorimetrically with leuco fuchsin, resulting in a color change from pale yellow to purple. The adsorption parameters, including the effect of pH, time, and formalin concentration, were also investigated. The adsorption isotherms for formalin in the MIPs and the non-imprinted polymer (NIP) were fitted to the Freundlich isotherm model, and the calculated average binding affinities for formalin were 0.44 and 0.13 mg g−1 for the MIPs and NIP, respectively. Good recoveries and precision ranging between 98% and 105%, with relative standard deviation (RSD) of <5% (n = 3) in the range 0–10 mg L−1, were obtained. The Stöber method for silica coating is often considered more environmentally friendly. Iit effectively prevents structural damage to imprinting sites and ensures an adsorption capacity loss of <5% after 3 months, making the approach more sustainable. This method can serve as an alternative to formaldehyde detection in food samples, offering operational efficiency, enhanced selectivity, and environmental benefits. This journal is © The Royal Society of Chemistry, 2026.
Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Negeri Jakarta, 13220, Indonesia; Department of Biology, Faculty of Mathematics and Natural Science, Universitas Negeri Jakarta, 13220, Indonesia; Department of Chemistry, Faculty of Science and Technology, State Islamic University (UIN) Syarif Hidyatullah Jakarta, Banten, Ciputat, 15412, Indonesia; Ministry of Energy and Mineral Resources – Lemigas, Jl. Ciledug Raya Kavling. 109, Jakarta, 12230, Indonesia; Badan Riset dan Inovasi Nasional, South Tangerang, 15314, Indonesia; School of Chemical Sciences, Universiti Sains Malaysia, Gelugor, Penang, 11800, Malaysia; Sethu Research and Innovation Centre (SRIC), Department of Chemistry, Sethu Institute of Technology, Tamil Nadu, Kariapatti, 626115, India
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