Electrochemical assay of the antioxidant ascorbyl palmitate in mixed medium

Electrooxidation of ascorbyl palmitate (AP) over gold screen-printed electrode (AuSPE) and gold nanoparticles modified graphite (AuNPs/gr) was examined in mixed water-alcohol medium. Voltammetric and amperometric studies showed that: (i) AP oxidation on the AuSPE proceeds at higher potential than on AuNPs/gr; (ii) the current density on AuNPs/gr was 2.4 times higher than on AuSPE; (iii) the linear dynamic range for AuNPs/gr doubled that for AuSPE. At the optimal for AuNPs/gr operating potential (250 mV) the following operational parameters were determined: sensitivity 1.627 ± 0.138 μA mM(-1) mm(-2); linearity up to 500 μM; LOD=5.8 μM. Quantification of the AP content in a real sample - stabilised flaxseed oil, was performed.