Metal ions, sensing/detecting

In contrast to metal ion sensing, QDs have been barely used for anion signaling. Toward this objective, Sanz-Medel et al. reported the functionalization of CdSe QDs with tert-butyl-A-(2-mercaptoethyl)-carbamate for the selective and sensitive detection of cyanide in methanol by analyte-induced luminescence quenching. In a further work, the authors prepared water-soluble CdSe QDs coated with 2-mercaptoethane sulfonate also for cyanide... 

For sensing of metal ions, the Gdm complex has to contain another coordination site, specific to the metal to be detected. This coordination center must show a high selectivity for the ion in question to avoid an undesired response due to interaction with other metal ions. 

A rather new approach for detecting metal ions with very high sensitivity and selectivity utilizes DNAzymes. DNAzymes are a special class of enzymes formed from DNA nucleotides. Compared to proteins and ribozymes, they are more stable, structurally simpler, and therefore cheaper. As DNAzymes often require metal ion cofactors, they are interesting sensing platforms for these metal ions [149]. 

In addition to metal ions, detection of halides such as fluoride is important, as the latter is often present in nerve gases and nuclear weapons manufacture. Our group utilized the unique reactivities of F with Si to specifically sense for fluoride ions [30]. PArE 35 was constructed with a masked precursor to a flu-... 

It is believed that two crowns bind a K+ ion, thus leading to loosely preassembled bis-pyrene subunits. When the metal ion recognition event occurs in the presence of y-CD, dramatic enhancements of excimer emission are observed, thus providing a method to selectively detect K+ ion in aqueous solution. This ability to sense an ionic analyte is unusual for CD chemosensors. Modification of 28 with other ion binding sites should provide a general method for cation detection. 

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