We report the first example of combining fluorescent probe-based freeze concentration effect with N-oxide chemistry for the highly sensitive and selective detection of ferrous ion (Fe(II)). Our preliminary results showed that the fluorescence intensity of Fe(II) was significantly enhanced upon freezing. Using a cryostage and confocal microscopy, the location of Fe(II) in the frozen state was successfully visualized. This novel approach offers a promising method for detecting Fe(II) with high sensitivity and specificity. -Scientific Journal cover by scapiens

https://pubs.rsc.org/en/content/articlelanding/2019/cc/c9cc05809e#!divAbstract