A novel lanthanide MOF thin film: The highly performance self-calibrating luminescent sensor for detecting formaldehyde as an illegal preservative in aquatic product

•A new luminescent thin film of Eu-NDC@HPAN have been fabricated on hydrolyzed polyacrylonitrile through layer by layer method.•The dual emissive Eu luminescent film is developed as a self-calibrating sensor for formaldehyde (0.05-1%) in aqueous solution.•The thin film of Eu-NDC@HPAN is applied to detect formaldehyde in sleeve-fish aqueous solution.•The lanthanide complex film is first used as a luminescent self-calibrating sensor for small molecules.

A continuous and well attached thin film of Eu3+ MOF with dual-emission was directly grown on hydrolyzed polyacrylonitrile (HPAN) using layer by layer approach. The structure and morphology of the luminescent Eu-NDC@HPAN thin film was investigated by XRD, FT-IR and SEM. The film was utilized as a self-calibrating luminescent sensor for detecting formaldehyde in aqueous solution. The emission intensity ratio (I453/I616) increased linearly with increasing formaldehyde content in the range from 0.05 to 1%. The sensing mechanism was also discussed. For practical purpose, the thin film has been applied to detect formaldehyde as an illegal preservative in aquatic product, This is first demonstrated that lanthanide complex luminescent film is application in self-calibrating small molecule sensors in biological systems successfully.

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