A highly selective, colorimetric, and environment-sensitive optical potassium ion sensor

We report a colorimetric K⁺sensor (KS7) for highly selective and accurate analysis of potassium ions. This sensor was demonstrated to be capable of analyzing potassium ions in urine with an experimental error of less than 5% using a ratiometric approach. Further, K⁺test strips can be easily prepared, which were used to detect K⁺in urine conveniently for daily health monitoring.