Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a) Preparation of ratiometric pH sensor based on PyrAPCN with dual fluorescence. Adapted with permission from ref (79). Copyright 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. (b) Structure of COF-HQ, its pH calibration curve, and fluorescence and optical images of the material after exposure to acidic solutions with specific pH levels. Reproduced with permission from ref (82). Copyright 2018 American Chemical Society.
