Spectrofluorimetric determination of nitrite with 5,6-diamino-1,3-naphthalene disulfonic acid

A simple, sensitive and specific spectrofluorimetric method for the determi nation of nitrite has been developed. It is based on the selective reaction of nitrite with 5,6-diamino-1,3-naphthalene disulfonic acid (DANDS) in aci dic medium to form 1-[H]-naphthotriazole-6,8-disulfonic acid, a highly fluo rescent compound in alkaline medium. The linear calibration range for nitri te was 0.8-112 ng ml(-1) with a 3 sigma detection limit of 0.09 ng ml(-1), lower than those of other spectrofluorimetric methods. The proposed method has been applied to the determination of nitrite in tap water (33 ng ml(-1) ) and lake water (17 ng ml(-1)) without extraction, with R.S.D. (n=6) of 1. 7 and 4.9%, respectively and recoveries of 98-102%. (C) 2000 Elsevier Scien ce B.V. All rights reserved.