Direct Determination of Vitamin C in Fruit Juices Using a Polyviologen-Modified Electrode

摘要: A polyviologen-modified glassy carbon electrode (PV-GCE) was applied to directly determine vitamin C (i.e., ascorbic acid) in deeply colored, viscous, and turbid fruit juice samples. Compared the results obtained at a bare GCE, oxidation of showed large increase current response PV-GCE pH 4 buffer solutions. Preconcentration is major factor for signal enhancement. Square-wave voltammetry (SWV) used detection PV-GCE. Under optimized conditions, SWV signals very wide linear range (up 900 μM) with slope regression coefficient 0.051 μM μA−1 0.998, respectively. The limit (S/N=3) 0.38 μM after 20 s accumulation open circuit. Since content value most juices are lower than 900 μM close 4, determination can be done without dilution other pretreatment demonstrated good precision agreement those method.