Rapid analysis of anionic and cationic surfactants in water by paper spray mass spectrometry† Ke Min, ‡a Qinglan Yang,‡a Xiangjing Zhong,a Donglan Yan,b Wei Luo,a Zhengfa Fang,a Jing Xiao,*c Ming Maa and Bo Chen *a Author affiliations * Corresponding authors a Key Laboratory of Phytochemical R&D of Hunan Province, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research of Ministry of Education, Hunan Normal University, Changsha 410081, China E-mail: dr-chenpo@vip.sina.com...