Visualized detection of water by modified metal organic framework-199 and its portable test paper with reversible color change

Abstract

Herein, we fabricate a melamine modified metal organic framework-199 composite (MOF-199@melamine), of which the structure is affected by the dynamics of the guest H2O molecule with significant color change. It realizes the visualized quantitative detection of water in a variety of organic solvents within 30 s. Moreover, DMF restored the original structure by replacing H2O molecules, realizing the regeneration of the materials. On this basis, PTFE-MOF-199@melamine test paper is developed to portably detect water content in organic solvents (maximum 0 %-98 % (v/v) water content) and ambient relative humidity (11–85 %). The test paper can be recycled four times with a regeneration rate higher than 90 %. The results are expected to solve the problems of existed electrochemical or fluorescence strategy such as the complicated operation process and signal output/reading system.