Determination of Trace Phosphoprotein in Food Based on Fluorescent Probe-Triggered Target-Induced Quench by...

Evaluation of the nutrition and determination of phosphoproteins is of great importance in different foods as aberrant phosphorylation changes many biological processes and can relate to health conditions. In this study, an ultrafast (5 min) and sensitive electrochemiluminescence (ECL) sensor was innovatively fabricated for the determination of phosphoproteins in foods on the basis of fluorescent probe NH₂-TiO₂/upconversion nanomaterials (UCNPs). Impressively, the ECL intensity of NH₂-TiO₂/UCNPs-rGO/GCE was remarkably enhanced by 29 times. Furthermore, the photoactive NH₂-TiO₂ layer provided not only specific selectivity but also a large surface area as well as an unprecedented photocatalytic activity for the NH₂-TiO₂/UCNPs-rGO/GCE ECL sensor (TIECLS), which could serve as an identification element for trace phosphoproteins. Under optimal conditions, the TIECLS achieved a relatively low detection limit of 9.2 × 10^-5 mg/mL (S/N = 3). Practical application of this TIECLS was carried out in different food samples with satisfying results, which were validated by laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS).