Amperometric gas sensor of arsine was developed using gold-modified diamond electrodes as the working electrodes. The detection method was conducted in high concentration of H(2)SO(4). The reaction was declared based on two oxidation steps, involving oxidation of As(3-) to As(0) at mild potential in strong acid. followed by electrochemical oxidation of As(0) to As(3+) at gold-based electrodes. Linear calibration curve was observed in the concentration range of 5-50 ppb (r(2) = 0.985) with detection limit of similar to 4.43 ppb (S/N = 3). Current decreasing of measurement was found similar to 5.5% for 5 measurements. However, better stability was observed after the 5th measurement, indicated that the sensor could be applied for long time measurement. Investigation to several possible interference gasses, i.e. SO(2), H(2)S, NO, NO(2), CO, O(3) and H(2) indicated no significant interference of the gas to arsine measurements. (C) 2010 Elsevier B.V. All rights reserved.