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) 3 2+-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) 3 2+ 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) 3 2+ , but also improved the stability of the ECL system. In addition, the enhancement mechanism of NGQDs on Ru(bpy) 3 2+ and quenching mechanism of PCP on Ru(bpy) 3 2+/NGQDs were investigated in detail. Under the optimum conditions, the as-fabricated sensor for ultrasensitive PCP determination expressed a wider linear range of 1 Â 10 À15 to 1 Â 10 À5 g mL À1 and a lower detection limit of 2 Â 10 À17 g mL À1 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.

Tris(2,2’‐bipyridyl)ruthenium(II)‐Nanomaterial Co‐Reactant Electrochemiluminescence

“…The conclusion was supported by the finding that conversion of primary amine on NCDs to tertiary amines through an Eschweiler‐Clarke methylation reaction could further increase the ECL enhancement. Furthermore, GQDs, nitrogen‐doped GQDs (NGQDs) and graphene oxide (GO) can also enhance anodic Ru(bpy) 3 2+ ECL by using amine group, carboxyl group, alcohols, phenols and other oxygenated groups as co‐reactant sites …”

“…With the discoveries, a plenty of ECL bio‐/chemo‐sensors have been developed by taking advantage of good biocompatibility of nanomaterials and the strong and stable ECL emission from Ru(bpy) 3 2+ /nanomaterials systems. For example, a signal‐off pentachlorophenol ECL sensor was fabricated based on the Ru(bpy) 3 2+ /NGQDs ECL system . In the presence of pentachlorophenol, the ECL intensity of Ru(bpy) 3 2+ /NGQDs system was quenched due to the energy transfer between electrooxidation product of pentachlorophenol and Ru(bpy) 3 2+ *.…”

“…Furthermore, GQDs, nitrogen-doped GQDs (NGQDs) and graphene oxide (GO) can also enhance anodic Ru(bpy) 3 2 + ECL by using amine group, carboxyl group, alcohols, phenols and other oxygenated groups as co-reactant sites. [28][29][30] Besides carbon nanomaterials, boron nitride quantum dots (BNQDs) and graphitic carbon nitride (g-CN) nanomaterials can enhance the anodic Ru(bpy) 3 2 + ECL as well due to the inherent amine-bearing groups on their surface. [31,32] The mechanism for inherent amine groups in BNQDs (or g-CN nanomaterials) involved Ru(bpy) 3 2 + ECL enhancement is similar to that for Ru (bpy) 3 2 + /TPA system, which is illustrated in Equations (1)-(5) by taking Ru(bpy) 3 2 + /BNQDs ECL system as an example.…”

“…For example, a signaloff pentachlorophenol ECL sensor was fabricated based on the Ru(bpy) 3 2 + /NGQDs ECL system. [29] In the presence of pentachlorophenol, the ECL intensity of Ru(bpy) 3 2 + /NGQDs system was quenched due to the energy transfer between electrooxidation product of pentachlorophenol and Ru(bpy) 3 2 + *. The detection limit of the ECL sensor was approaching sub-femtomolar level.…”

Highly Sensitive and Selective Detection of Pb(II) by NH2−SiO2/Ru(bpy)32+−UiO66 based Solid‐state ECL Sensor

“…Figure 4A showed that the optimal volume of NH 2 À SiO 2 was 4.0 μL. It was because that more ECL luminophore Ru(bpy) 3 2 + was modified on the GCE surface and produced more excited states of Ru (bpy) 3 2 + * [41]. Excessively adding of Ru(bpy) 3 2 + À UiO66 caused the quenching of ΔECL intensity, since too thick film modified on GCE surface hindered the electron transfer rate.…”