Highly sensitive electrocatalytic detection of nitrite based on SiC nanoparticles/amine terminated ionic liquid modified glassy carbon electrode integrated with flow injection analysis

摘要

Herein, we report a new chemically modified electrode as highly sensitive and selective amper-ometric nitrite sensor based on a nanocomposite containing an amine-terminated ionic liquid (1-(3-Aminopropyl)-3-methylimidazolium bromide) and silicon carbide nanoparticles (NH_2-IL/SiCnp). The scanning electron microscopy (SEM) technique was used to examine the morphology of NH_2-IL/SiCnp modified glassy carbon (GC) electrode. It was found that SiCnp/IL layer was uniformly formed on the electrode surface. The modified electrode showed excellent electrocatalytic activity toward nitrite oxidation compared to the bare GC, NH_2-IL/GC and SiCnp/GC electrodes. The nitrite oxidation peak current (I_p) at NH_2-IL/SiCnp/GC was 3.5 and 1.6-fold higher than that of bare GC and SiC/GC electrodes, respectively, with the peak potential appeared at +0.77 V, roughly 180 and 60 mV lower potential than bare GC and SiCnp/GC electrodes, respectively. Linear relationship between amperometric current response and nitrite concentration was observed in the range from 50 nM to 350 μM and the limit of detection was 20 nM (S/N = 3). In addition, the modified electrode has an excellent anti-interference property in the presence of other potential interfering species as well as a good operational stability and good antifouling properties. The nitrite detection ability of the NH_2-IL/SiCnp/GC electrode was further demonstrated using flow injection analysis (FIA). The repeatability of the electrode response in the flow injection analysis (FIA) configuration was evaluated as 2.2% (n= 12), and the detection limit of the method was estimated to be 0.3 μM (S/N = 3). Based on the above results, the proposed system appears to be a highly efficient platform for the development of sensitive and stable nitrite electrochemical sensor.