Unmonitored discharge of heavy metal ions loaded industrial effluents is a major source of water pollution. Among the heavy metals, arsenic is the most detrimental. The current work presents the designing of a simple and efficient electrochemical sensing platform which can detect As(III) in water below its concentration level declared permissible by the World Health Organization. Electrochemical impedance spectroscopy and cyclic voltammetry offered evidence for faster electronic transport through the modified glassy carbon electrode. Square wave anodic stripping voltammetry was carried out to probe the role of the recognition layer of L-tryptophan in facilitating electron transfer between the analyte and the transducer. For getting the best response of the As(III) ions at the designed sensor, conditions such as pH of the medium, accumulation time and deposition potential were optimized. The limit of detection (LOD) of As(III) ions with a value of 12 pM was obtained which confirms the sensitivity of the designed sensor. High percentage recovery from real water samples suggested practical applicability of the proposed method for As(III) ion detection. Computational studies supported the experimental result of the role of the recognition layer of L-tryptophan in pre-concentrating the analyte at the electrode-electrolyte interface.