Highly sensitive voltammetric determination of dexamethasone on amalgam film electrode

A new, simple and highly sensitive method of dexamethasone (DM) voltammetric determination was successfully developed. Low limit of detection has been obtained using amalgam film silver based electrode (Hg(Ag)FE) as the working electrode. The electrochemical behaviour of dexamethasone reduction on Hg(Ag)FE was investigated using cyclic voltammetry. A linear voltammetric response was obtained for DM in the concentration range from 2.50.10(-9) mol L-1 (9.16.10(-7) g L-1) to 2.25.10(-7) mol L-1 (8.83.10(-5) g L-1), with a detection limit of 1.640(-9) mol L-1 for preconcentration time of 45 s. Repeatability of method was determined as RSD % for dexamethasone concentration of 0.1.10(-6) mol L-1 as 1.6% (n = 5). The proposed method was successfully applied and validated by studying the recovery of dexamcthasone in commercially available drugs.