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一、引言有不少有机化合物如二甲乙二醛肟,8-羟基喹啉等能与一些金屬离子結合成内絡合物,在分析化学上得到广泛的应用。由于这些内絡合物都是不带电荷,难溶于水,可和它們作用的金屬也不多,而且絡合程度不能借氢离子的濃度来控制,所以这类絡合剂的用途,仅局限于对鉄、鈷、镍、鋅、鎘及鋁等少数金屬的重量分析、比色分析或萃取分离等方面,而不能应用于直接滴定。近十年来發現一系列的氨基多元羧酸如氨三乙酸、乙二氨四乙酸(以下簡称乙二四乙)、隣(艹巳)二氨四乙酸等化合物,能
I. INTRODUCTION There are many organic compounds such as dimethyl glyoxime, 8-hydroxyquinoline and other metal ions can be combined into an internal complex, the analytical chemistry has been widely used. Since these internal complexes are both uncharged, poorly soluble in water and not much to work with, and the degree of complexation can not be controlled by the concentration of hydrogen ions, the use of such complexing agents is limited It can not be applied to direct titration in gravimetric analysis, colorimetric analysis or extraction and separation of a few metals such as cobalt, nickel, zinc, cadmium and aluminum. In the past ten years, a series of compounds of aminopolycarboxylic acids such as nitrilotriacetic acid, ethylenediaminetetraacetic acid (hereinafter referred to as ethylenediaminetetraacetic acid) and o-aminobutyric acid