光气(COCl_2)是染料、医药、农药等有机合成的重要原料,常温下为无色气体,是窒息性剧毒物质。当空气中浓度为0.1毫克/升时,逗留30～60分钟人即致死,空气中最大允许浓度为0.0005毫克/升,因此,对车间空气中光气含量进行经常性监测是必不可少的。光气测定方法主要有碘化钾法(容量法)、 Phosgene (COCl_2) is an important raw material for organic synthesis such as dyes, pharmaceuticals and pesticides. It is a colorless gas at room temperature and is a highly toxic asphyxiant material. When the air concentration of 0.1 mg / L, the stay of 30 to 60 minutes is dead, the maximum allowable concentration in the air of 0.0005 mg / L, therefore, on the workshop air phosgene content of the regular monitoring is essential. Phosgene determination of potassium iodide method (capacity method),