Selective response of dopamine in the presence of ascorbic acid on carbon paste electrode modified with titanium phosphated silica gel

Titanium phosphate grafted on the surface of silica gel (devoted briefly as Si-TiPH) was synthesized and used as bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The Si-TiPH bulk modified carbon paste electrode was used for the selective determination of dopamine (DA) in the presence of ascorbic acid (AA). The modified electrode offers an excellent and stable response for the determination of DA in the presence of AA. The differential pulse voltammetry peak current was found to be linear with the DA concentration in the range 2 × 10−7 to 1 × 10−6 and 2 × 10−6 to 6 × 10−5 mol L−1. The detection limit of the proposed method in the presence of 2.0 × 10−5 M of AA was found to be 4.3 × 10−8 mol L−1 for DA determination. The proposed method was successfully applied for the determination of DA in injections.