在聚乙烯醇（ＰＶＡ）存在下，耐尔蓝（ＮＢ）与抗钼杂多酸络阴离子形成离子缔合物，其最大吸收位于５８５ｎｍ，表现摩尔吸光系数ε＝３．５９×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，服从比尔定律范围０～２μｇＳｃ／２５ｍｌ，测定极限３，０ｎｇＳｃ／ｍｌ（ｎ＝７），对于０．０４μｇＳｃ／ｍｌ测定的相对标准偏差ＲＳＤ＝２．８％（ｎ＝１０）。离子缔合物的摩尔组成为Ｓｃ：Ｍｏ：ＮＢ＝１：１２：３。本法已用于地质样品中钪的测定，结果满意。 In the presence of polyvinyl alcohol (PVA), Nile blue (NB) forms an ionic association with the antimolybdenum heteropolyanion anions, with a maximum absorption at 585 nm, exhibiting a molar absorptivity of ε = 3.59 × 105 L · mol- 1 · cm -1, obeying Beer’s law range of 0-2 μg Sc / 25 ml, limit of determination of 3.0 ng / ml (n = 7), relative standard deviation RSD of 2.8% (n = 10 ). The molar composition of the ionic complex is Sc: Mo: NB = 1: 12: 3. This method has been used for the determination of scandium in geological samples with satisfactory results.