Voltammetric determination of hyaluronic acid based on its interaction with phenosafranine

In this paper, a cationic dye of phenosafranine (PSF) was selected as a bioprobe to determine hyaluronic acid (HA) by linear sweep voltammetry on the dropping mercury working electrode (DME). In pH 4.5 Britton-Robinson (B-R) buffer solution, PSF has a well-defined second order derivative linear sweep voltammetric reductive peak at −0.42 V (vs. SCE). After the addition of HA into the PSF solution, the reductive peak current decreased apparently without the movement of reductive peak potential. Based on the decrease of the reductive peak current, a new voltammetric method for HA determination was established. The conditions for the interaction and the electrochemical detection were optimized and the interference substances for the detection were investigated. Under the optimal experimental conditions the difference of peak current was directly proportional to the concentration of HA in the range from 0.8 to 50.0 mg/l with the linear regression equation as Δip″ (nA) = 93.85 + 22.92c (mg/l) (n = 14, γ = 0.995) and the detection limit was calculated as 0.901 mg/l (3). This new method was further applied to determine the HA content in the synthetic samples with satisfactory results and good recovery. The stoichiometry of PSF-HA complexes was calculated and the binding mechanism was also discussed.