Samarium-Based Turn-Off Fluorescence Sensor for Sensitive and Selective Detection of Quinolinic Acid in Human Urine and Serum

Quinolinic acid (QA) is an index for some diseases, whose detection is of importance. This work presents a samarium metal-organic framework (Sm-MOF) containing 5-sulfoisophthalate ligand (SIP3-). The fluorescence of Sm-MOF integrates the emission at 339 nm from the SIP3- ligand and four characteristic (4)G(5/2) -> H-4(j) (j = 5/2, 7/2, 9/2, and 11/2) transitions at 559, 596, 642, and 701 nm from Sm(III). Sm-MOF as a turn-off fluorescence sensor to QA exhibits high sensitivity, selectivity, and durability. The fluorescence quenching response to QA shows a linear relationship of I-0/I = 0.00496middotC(QA) + 1.12474 in the QA concentration of 0-500 mu M and a limit of detection calculated as 4.11 mu M. Sm-MOF shows the structural and fluorescent stabilities in five quenching-recovery cycles. The recoveries of close to 100% in human urine and serum indicate high reliability. The paper-based Sm-MOF sensor displays a rough QA quantitative analysis by recognizing red values in the on-site QA detection.