Construction of a New Sensor with Copper(II) Complex Anchored in Calcium Phosphate Intercalated with m-Aminobenzoic Acid and Their Application in Determination of Dopamine

Crystalline lamellar calcium phosphate retained m-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1,033 cm−1 and 1,010 cm−1 intervals confirmed the presence of the phosphate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 535 pm and 947 pm for the original and the intercalated compounds, respectively. The adsorption isotherm of copper(II) on a calcium phosphate host intercalated with m-aminobenzoic acid was studied in ethanol solution to give a maximum adsorption capacity of 1.43 mmoL g−1. The material was incorporated into carbon paste electrode and its electrochemical properties were investigated. However, for a dopamine solution, an enhancement of the anodic peak current was detected due to the electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for dopamine determination in pharmaceutical preparation (one commercial sample (Revivan)) with success.