Abstract

We report an electroanalytical methodology for determining As(III) in natural waters using adsorptive stripping voltammetry with a Screen-printed carbon nanotube electrode modified with Alginate (ALG) from brown algae (CNTALG-SPE). The optimal conditions chosen in the electrode preparation were: CALG: 2.5 mg mL−1; CHNO3 0.01 mol L−1; Eacc:-0.70 V and tacc: 900 s. Subsequently, the modified electrode (CNTALG-SPE) was used in the As(III) determination without accumulation step. The peak current was proportional to the As(III) concentration up to 25.0 μg L−1 (R = 0.992), with a 3σ detection limit (DL) of 2.8 μg L−1. Finally, the method was validated using laboratory drinking water spiked with As(III) and was applied to the determination of As(III) in water samples from the Loa River (North of Chile) which contained As(III) and As(V). The results of the proposed method were compared with those obtained by adsorptive stripping voltammetry with HMDE and by Inductively Coupled Plasma Mass Spectrometry (ICP − MS. Astotal) techniques. © 2025 Elsevier B.V.