Determination of pentachlorophenol by anodic electrochemiluminescence of Ru(bpy)32+ based on nitrogen-doped graphene quantum dots as co-reactant

Abstract

Sensitive and quantitative analysis of pentachlorophenol (PCP) is especially important in the field of ecology and agriculture. Herein, a highly sensitive and stable Ru(bpy)₃²⁺-based anodic electrochemiluminescence (ECL) system utilizing nitrogen-doped graphene quantum dots (NGQDs) as a novel co-reactant was firstly constructed to detect PCP. In this system, Ru(bpy)₃²⁺ was used as luminophor, while NGQDs were applied as co-reactant in place of the toxic and volatile tripropylamine. The novel co-reactant not only promoted the luminous efficiency of Ru(bpy)₃²⁺, but also improved the stability of the ECL system. In addition, the enhancement mechanism of NGQDs on Ru(bpy)₃²⁺ and quenching mechanism of PCP on Ru(bpy)₃²⁺/NGQDs were investigated in detail. Under the optimum conditions, the as-fabricated sensor for ultrasensitive PCP determination expressed a wider linear range of 1 × 10⁻¹⁵ to 1 × 10⁻⁵ g mL⁻¹ and a lower detection limit of 2 × 10⁻¹⁷ g mL⁻¹ with good stability and repeatability. Furthermore, based on the distinctive advantages of the novel ECL sensor, it was successfully used to detect PCP in tap water and river water, and satisfactory recoveries were obtained.