Voltammetric study of polyviologen and the application of polyviologen-modified glassy carbon electrode in amperometric detection of vitamin C

• Published in: Journal of applied electrochemistry 2008-09, Vol.38 (9), p.1285-1292
• Main Authors: Hsu, P.-F., Ciou, W.-L., Chen, P.-Y.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Electrochemistry; Industrial Chemistry/Chemical Engineering; Original Paper; Physical Chemistry
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-008-9555-x

The voltammetric behavior of viologen oligomers prepared from butylviologen dibromide and the factors influencing polyviologen film formation were investigated at a glassy carbon electrode (GCE). Based on the voltammetric observations, phosphoric acid is crucial to the formation of a stable polyviologen film on a GCE. The polyviologen-modified glassy carbon electrode (PVGCE) was employed to determine vitamin C (i.e., ascorbic acid) in order to demonstrate the electroanalytical application of the electropolymerized polyviologen film. The PVGCE was found capable of accumulating vitamin C at electrode surface in a slightly basic solution (pH = 7.8) and induce a negative shift of oxidation potential of vitamin C. Vitamin C was detected by hydrodynamic amperometry at +0.1 V (vs. Ag/AgCl) in a batch-injection cell; no accumulation time is required. The dependence of oxidation current on concentration was linear from 5.00 × 10 −7  M to 1.22 × 10 −4  M with a regression coefficient of 0.9993. Several real samples were analyzed and the results exhibit good agreement with those determined by iodimetric titration.