Fluorometric Detection of Thiamine Based on Hemoglobin-Cu₃(PO₄)₂ Nanoflowers (NFs) with Peroxidase Mimetic Activity

Component analysis plays an important role in food production, pharmaceutics and agriculture. Nanozymes have attracted wide attention in analytical applications for their enzyme-like properties. In this work, a fluorometric method is described for the determination of thiamine (TH) (vitamin B₁) based on hemoglobin-Cu₃(PO₄)₂ nanoflowers (Hb-Cu₃(PO₄)₂ NFs) with peroxidase-like properties. The Hb-Cu₃(PO₄)₂ NFs catalyzed the decomposition of H₂O₂ into ·OH radicals in an alkaline solution that could efficiently react with nonfluorescent thiamine to fluoresce thiochrome. The fluorescence of thiochrome was further enhanced with a nonionic surfactant, Tween 80. Under optimal reaction conditions, the linear range for thiamine was from 5 × 10^-8 to 5 × 10^-5 mol/L. The correlation coefficient for the calibration curve and the limit of detection (LOD) were 0.9972 and 4.8 × 10^-8 mol/L, respectively. The other vitamins did not bring about any obvious changes in fluorescence. The developed method based on hybrid nanoflowers is specific, pragmatically simple and sensitive, and has potential for application in thiamine detection.