Water Stable [Tb4] Cluster-Based Metal–Organic Framework as Sensitive and Recyclable Luminescence Sensor of Quercetin

High Resolution Image Download MS PowerPoint Slide A novel 3D metal–organic framework (MOF){[Tb 3 (CBA) 2 (HCOO)(μ 3 -OH) 4 (H 2 O)]·2H 2 O·0.5DMF} n ( S - 1 ) was synthesized by the solvothermal method. The crystal structure indicates that [Tb 4 O 4 ] cubane clusters self-assemble into an infinite chain by sharing vertex, which is further linked to adjacent chains through 1,1-cyclobutanedicarboxylic acid ligand (H 2 CBA), resulting in a honeycomb arrayed framework. S - 1 possesses excellent water stability and still retains intact structure after exposure to water for 10 weeks or boiling water for 10 weeks. Interestingly, S - 1 acts as a luminescence sensor to selectively and sensitively detect quercetin with the limit of detection (LOD) as low as 0.23 ppm (7.6 × 10 –7 M). The relationship between relative luminescence intensity and concentration obeys linear in the range of 0–300 ppm (0–993 μM), which allows quantitative detection of quercetin. Importantly, S - 1 can be reused at least six times with almost no change in luminescent intensity. Compared with the high performance liquid chromatography–mass spectrometry (HPLC–MS) method, S - 1 was used to determine the content of quercetin in onionskin and apple peel samples with satisfactory results. Furthermore, a portable S - 1 test paper is also developed and expected to be applied in practice. To our knowledge, S - 1 is the first example of MOFs as luminescent sensor for quercetin.