A polymerizable rhodamine-based monomer 2-(3-(2-(3',6'-bis(diethylamino)-3-oxospiro[isoindoline-1,9'-xanthen]-2-yl)ethyl)ureido)ethyl acrylate (RhBUEA) is first designed and synthesized, and then used in the preparation of a new water-soluble P(AM-co-RhBUEA) through precipitation polymerization of it with acrylamide (AM). Influence of the RhBUEA content on the polymerization process is investigated, and the chemical structure and composition of the copolymers are confirmed by FTIR and UV-Vis spectral analysis. According to the off-on switch between spirolactam and ring-opened form of rhodamine derivative, P(AM-co-RhBUEA) prepared with 15 wt.% RhBUEA exhibits a highly sensitive and selective recognition towards Fe³⁺ in aqueous solution with 0.073 μM of detection limit, accompanied with a remarkable spectral and color change. Furthermore, the spectral response is reversible by the alternating addition of Fe³⁺ and EDTA to the copolymer, and the test strips prepared by P(AM-co-RhBUEA) can detect Fe³⁺ colorimetrically and portably, which makes the water-soluble polymer a promising Fe³⁺ sensor in the field of on-site detection.

可聚合的若丹明类单体丙烯酸2-（3-（2-（3'，6'-双（二乙氨基）-3-氧代螺并[异吲哚啉-1,9'-黄嘌呤] -2-基）乙基）脲基）丙烯酸乙酯（RhBUEA）首先进行设计和合成，然后通过将其与丙烯酰胺（AM）沉淀聚合而用于制备新的水溶性P（AM-co-RhBUEA）。研究了RhBUEA含量对聚合过程的影响，并通过FTIR和UV-Vis光谱分析确定了共聚物的化学结构和组成。根据螺内酰胺和若丹明衍生物的开环形式之间的关闭开关，用15 wt。％RhBUEA制备的P（AM- co- RhBUEA）对Fe ³⁺具有高度敏感和选择性的识别水溶液的检测极限为0.073μM，并伴有明显的光谱和颜色变化。此外，通过向共聚物中交替添加Fe ³⁺和EDTA ，光谱响应是可逆的，并且P（AM-co-RhBUEA）制备的测试条可以比色和便携式地检测Fe ³⁺，这使得水溶性聚合物在现场检测领域是很有前途的Fe ³⁺传感器。