Aluminum(III)-Selective Screen Printed Sensor Based on Methyl Red

Resumo

Modified screen printed electrode (MSPE) with 2-[[4-(dimethyl amino) phenyl] diazenyl] benzoic acid (Methyl Red) was prepared for determination of aluminum ions in water and pharmaceutical (Maalox and Epicogel) samples. The MSPE reveals linear response over a wide concentration range of 5.0 × 10^–6–1.0 × 10^–2 mol L^–1 of aluminum at 25°C with a trivalent cationic slope of 20.4 ± 0.5 mV decade^–1 with detection limit 5.0 × 10^–6 mol L^–1 in pH range 3–5. Moreover, the mechanism of chemical reaction between Methyl Red and aluminum ions on the sensor surface was studied using IR spectra, energy dispersive X-ray analysis (EDX) and scanning electron microscope (SEM). The prepared sensor also showed reproducible and stable response over a period of 14 week with fast response time about 5 s. The proposed potentiometric method was validated according to the IUPAC recommendations. The results obtained from the proposed sensor were comparable with those obtained with inductively coupled plasma mass spectrometry (ICP–MS).