凱氏定氮法疑問

 請qing問wen在zai用yong凱kai氏shi定ding氮dan法fa測ce定ding蛋dan白bai質zhi時shi，樣yang品pin一yi開kai始shi碳tan化hua起qi泡pao濺jian在zai管guan壁bi上shang，後hou隨sui溫wen度du升sheng高gao又you重zhong新xin流liu回hui硫liu酸suan中zhong消xiao解jie，最zui後hou仍reng是shi澄cheng清qing液ye
，且qie管guan壁bi不bu再zai有you黑hei色se物wu質zhi，這zhe種zhong情qing況kuang下xia氮dan有you損sun失shi嘛ma？