Hydroxyethyl cellulose-boosted electrochemiluminescence sensor based on velvet-like g-C₃N₄ for ultrasensitive...

This study pioneers the incorporation of hydroxyethyl cellulose (HEC) into electrochemiluminescence (ECL) sensing strategy. By modifying a novel velvet-like graphitic carbon nitride (V-g-C₃N₄) with exceptional conductivity and luminescent properties, we successfully constructed a highly sensitive ECL sensor based on HEC-functionalized V-g-C₃N₄ (HEC/V-g-C₃N₄). The incorporation of HEC ensured stable immobilization of V-g-C₃N₄ on glassy carbon electrode surface. This facilitated the generation of more excited-state species, which significantly enhanced the ECL signal intensity. Compared to the commonly used chitosan-functionalized V-g-C₃N₄ (CS/V-g-C₃N₄), HEC/V-g-C₃N₄ exhibited a 4.35-fold enhancement in ECL intensity. Thus, HEC/V-g-C₃N₄ was applied in ECL sensors for the ultra-sensitive detection of 3-nitro-l-tyrosine (3-NT) in human saliva. Under optimized conditions, the sensor demonstrated a wide detection range (1 × 10^-10 - 1 × 10^-5 M) and an exceptionally low detection limit (2.8 × 10^-11 M). When applied to the detection of 3-NT in saliva samples, the sensor achieved high accuracy, with recoveries ranging from 96.77% to 106.1% and relative standard deviations between 1.15% and 5.56%. The results highlight the ECL sensor's excellent selectivity, stability, and reproducibility, offering a novel, reliable, and cost-effective platform for the high-sensitivity detection of 3-NT in saliva from healthy individuals.