本文介绍了一种用来测定天然水中铁(Ⅱ)的新试剂:4-(2-噻唑基偶氮)-6-氯-间苯二酚(TACR),其原理是:该试剂能灵敏地与二价铁起反应生成水溶性棕色络合物,它在741nm处有最大吸收。该法的特点是:简单、快速、灵敏、选择性强,测定1.0ppm Fe~(2+)时,水中共存的下列物质不干扰:Ca~(2+) 、Mg~(2+)、Sr~(2+)、Ba~(2+)、Hg~(2+)、As~(5+)、Mo~(6+)、Se~(4+)、Tl~(3+)、Li~+、 This paper presents a new reagent for the determination of iron (Ⅱ) in natural water: 4- (2-thiazolyl azo) -6-chloro- resorcinol (TACR) Reacts with ferrous iron to form a water-soluble brown complex, which has a maximum absorption at 741 nm. The method is characterized by simple, rapid, sensitive and selective. When 1.0ppm Fe ~ (2+) is detected, the following substances coexist in the water do not interfere: Ca2 +, Mg2 + (2 +), Ba2 +, Hg2 +, As5 +, Mo6 +, Se4 +, Tl3 +, Li2 + +,