Study of ethosuximide detection using a novel molecularly imprinted electrochemiluminescence sensor based on tris(2,2′-bipyridyl) ruthenium(II)@nitrogen doped graphene quantum dots

A novel molecularly imprinted electrochemiluminescene (ECL) sensor was fabricated for the detection of ethosuximide. The new Ru(pby)32+@N-GQDs (tris(2,2′-bipyridyl) ruthenium(II)@nitrogen doped graphene quantum dots) nanocomposite was synthesized by electrostatic interaction between Ru(pby)32+ and N-GQDs, which showed excellent and stable ECL properties. And then dopamine as functional monomer and ethosuximide as template molecule were co-polymerized by hydrogen bonding on the surface of Ru(pby)32+@N-GQDs/Nafion. After ethosuximide was extracted with H2SO4, the molecularly imprinted cavities in film were formed. When ethosuximide rebound onto imprinted cavities again, the ECL intensity of Ru(pby)32+@N-GQDs decreased. Based on this principle, the quantitative relationship between the concentration of ethosuximide (c) and the variation of ECL intensity (ΔIECL) was established. Namely the ΔIECL depended linearly on the log c in the range from 5.00 × 10−7 to 1.00 × 10−4 mol/L with a detection limit of 3.00 × 10−7 mol/L (S/N = 3), and the correlation coefficient was 0.9984. The proposed sensor was also applied in plasma and urine samples with recovery in range from 97.80% to 106.2% (RSD < 6.3%).