Colorimetric detection of acidic pesticides in water.

A water-stable, porphyrin-based metal-organic framework (MOF) produces a distinct colour change in response to acids' p K a and concentrations. This colour change is associated with the protonation of the N-atoms within the porphyrin ligand present in the MOF structure. As a proof-of-concept, we demonstrate the use of this MOF for detecting traces of different acidic pesticides present in water samples spontaneously.