Individual and simultaneous electrochemical determination of metanil yellow and curcumin on carbon quantum dots based glassy carbon electrode

Abstract

Adulteration of medicinally valuable curcumin (CU) with harmful chemicals as metanil yellow (MY) in recent years have demanded for quick detection techniques of the adulterants. The voltammetric behavior of CU and MY on bare glassy carbon electrode (BGCE) and carbon quantum dots modified glassy carbon electrode (CQDs/GCE) was studied by both cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in phosphate buffer solution of pH 5.4. The MY responded to the CQDs/GCE with two anodic peaks at -0.004 V and 0.136 V and two cathodic peaks at -0.112 and -0.048 V. Under similar conditions CU exhibited two anodic peaks at 0.28 V and 0.55 V and one cathodic peak at 0.25 V. The overlapped voltammogram obtained for CU and MY on BGCE was well separated on the CQDs/GCE. The interference studies revealed that the compounds, demethoxycurcumin and bisdemethoxycurcumin, which are commonly associated with CU, did not interfere with the detection of MY. Real sample was analyzed with fabricated electrode and the recovery values >98% were obtained.

Keywords: Carbon quantum dots; Curcumin; Cyclic voltammetry; Differential pulse voltammetry; Metanil yellow.