A new Schiff base sensor (E)-N'-((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)methylene)-5-(thiophen-2-yl)oxazole-4-carbohydrazide (TOQ) was synthesized and found to emit yellowish green fluorescence upon introduction of In³⁺. Furthermore, the resulting complex TOQ-In³⁺ was quenched selectively by Fe³⁺. The detection limits of TOQ for In³⁺ and Fe³⁺ were 1.75 × 10^-10 M and 8.45 × 10^-9 M, respectively. The complex stoichiometry of TOQ with target ions was determined to be 1:2 via Job’s plot analysis, which further was verified by ESI-MS titration and theoretical calculations. Moreover, TOQ can be used for the determination of target ions in environmental water samples. A portable paper sensor of TOQ was successfully developed for detecting In³⁺ to assess its applicability.

新型席夫碱传感器 ( E )- N' -((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1- ij ]quinolin-9-yl)methylene)合成了-5-(thiophen-2-yl)oxazole-4-carbohydrazide ( TOQ )，发现在引入 In ³⁺时会发出黄绿色荧光。此外，生成的复合物TOQ -In ³⁺被 Fe ³⁺选择性淬灭。In ³⁺和Fe ^3+的TOQ检测限分别为1.75 × 10 ^-10 M 和8.45 × 10 ^-9 M。TOQ的复杂化学计量通过 Job's plot 分析确定与目标离子的比例为 1:2，并通过 ESI-MS 滴定和理论计算进一步验证。此外，TOQ可用于测定环境水样中的目标离子。成功开发了用于检测 In ^3+的TOQ便携式纸张传感器，以评估其适用性。