Lanthanide doped metal−organic framework: novel turn-on fluorescent sensing of iodide in kelp and seawater samples

An effective fluorescence sensor was developed for iodide detection, with copper-based metal−organic frameworks (Cu-BTC) into which Tb3+ was doped by post modification. Tb@Cu-BTC manifested the characteristic emission of Tb3+ resulted from efficient sensitization through antenna effect, which was further exploited as a "turn-on" fluorescence probe to determinate iodide in aqueous solution. The sensor exhibited two great linear ranges of 12.5 ∼ 40 μM and 40 ∼ 160 μM, with a good limit of detection of 4.7 μM for iodide. These results showed that Tb@Cu-BTC exhibited high selectivity, excellent stability and great anti-interference capability for iodide monitoring. The possible mechanism could be object-induced luminescence. In addition, recovery experiments have been carried out to determine iodide in kelp standard sample, tap water and sea water. This method based on Tb@Cu-BTC could also be potentially employed to determinate iodide in other samples.