Method and device for preparing stable arsenic trioxide standard gas

The invention provides a method for preparing stable arsenic trioxide standard gas. The method comprises the following steps of generating hydride of arsenic, namely reacting sodium arsenite with hydrochloric acid and potassium borohydride to generate arsenic hydride gas and hydrogen, and separating through a gas-liquid separator; carrying out atomization of arsenic, namely introducing the separated arsenic hydride gas and hydrogen into an atomization reactor through carrier gas, carrying out pre-heating at a certain temperature, and atomizing the arsenic hydride gas into arsenic atoms throughflames at a furnace opening of an atomizer; oxidizing the arsenic atoms, namely mixing the atomic arsenic with the nitrogen oxygen gas in a gas mixing chamber and bringing the mixture into a high-temperature electric heating furnace, and fully combining with oxygen at a certain temperature to generate arsenic trioxide; and absorbing the tail gas. According to the method and the device, solution supply ratio parameters ar