Improvement of Voltammetric Detection of Sulfanilamide with a Nanodiamond?Modified Glassy Carbon Electrode

摘要

Owing to its high hardness, high chemical inertness, and good biocompatibility, nanodiamond (ND) hasrecently been increasingly used in electrochemical analysis. In this work, a comparative study ofvoltammetric detection of sulfanilamide using a bare glassy carbon electrode (GCE) and ND-modifiedglassy carbon electrode (GCE?ND) was carried out. Scanning electron microscopy (SEM) and cyclicvoltammetry (CV) analyses revealed that modification of a GCE with 100 μL of ND suspension (40mg·L ?1 ) was the optimum condition in this study. The results of CV analyses with the [Fe(CN) 6 ] 3? redoxcouple suggested the occurrence of a diffusion-controlled process on both electrodes. However, theGCE?ND exhibited a larger electroactive surface area and a higher heterogeneous electron transfer rateconstant, which were approximately 2.11 and 5.05 times greater than those of the bare GCE, respectively.When applied to the detection of sulfanilamide solution using square wave voltammetry under theoptimum conditions, the bare GCE showed a linear dynamic range of 1?80 mg·L ?1 (R 2 = 0.9994) witha detection limit of 0.744 mg·L ?1 , by contrast, the GCE?ND showed a linear dynamic range of 0.2?100mg·L ?1 (R 2 = 0.9949) with a detection limit of 0.161 mg·L ?1 . The detection limit of the GCE?ND wasas much as 78.4% lower than that of the bare GCE. Furthermore, interday detection experiments revealedthat the GCE?ND had higher repeatability and accuracy than the bare GCE.