Dual-selective capture and rapid detection of phosphoprotein in food by using lignin mediated Zr-based quantum dots...

Fast and accurate detection-method for phosphoprotein (β-casein) is very important in evaluation of functional properties for food proteins and prevention the occurrence of early diseases. Herein, a novel concept, surface-tethered electrochemiluminescence (ECL) analysis, was proposed for meeting the demand for dual recognition and ultra-fast (20 s) detection of β-casein directly. The validation system based on lignin-mediated Zr-based quantum dots probe (QDs-AL@Zr) not only performed well in ECL behavior, but also conducted to efficiently enrich-to-test β-casein online. In a proof-of-concept trial, the prepared Au-electrode (AuE/TiO₂) is modified with a monolayer consisting of TiO₂, to absorbe β-casein and QDs-AL@Zr by TiO₂-β-casein-Zr matching. Subsequently, β-casein level could be determined by target-induced ECL-intensity. The proposed sensor displayed strong affinity for β-casein due to the coexistence of Zr-O-P and Ti-O-P clusters and presented a low detection limit reaching 5.7 × 10^-8 mg/mL. Significantly, the proposed dual-selective ECL sensor was obtained satisfactory results at different food samples.