DIFFERENTIAL PULSE ADSORPTIVE VOLTAMMETRY FOR DETERMINATION OF PROCAINE HYDROCHLORIDE ON PUMIC MODIFIED CARBON PASTE ELECTRODE

AIM: To study an adsorptive voltammetric method for determination of procaine hydrochloride using a new chemically modified electrode, and discuss the possible electrode reaction mechanism. METHODS: In a base solution of 1.25×10 ^-3 mol·L^-1 KH₂PO₄ and 1.25×10_-3 mol·L^-1 Na₂HPO₄ buffer solution (pH 6.88, 25℃), procaine hydrochloride was determined by differential pulse adsorptive voltammetry using a 6% pumic modified carbon paste electrode. Scan rate: 10 mV·s^-1 ; pulse height: 50 mV; pulse period: 0.5s; sensitivity of potentiostat: 2×10 ^-9 A·mV^-1. RESULTS: The peak potential of anode was +0.98 V (vs .SCE). There was a good linear relationship between the peak current and the concentration of procaine hydrochloride in the range of 9.1×10^-7～2 .6×10^-5 mol·L^-1 . The detection limit of the method was 5.0×10^-8 mol·L^-1 . The recovery was 95.2%～104.8%, and the relative standard deviation was 3.2% (n=10). CONCLUSION: This method was rapid, simple, accurate and highly sensitive. The procaine hydrochloride injection had been determined with good results. The electrode reaction of procaine hydrochloride was irreversible process with two electrons and two protons on the carbon paste electrode.