Sensing for lithium ions

Daniel Stubing High Res Edit 005521 March 2016:

CNBP researchers Daniel Stubing, Sabrina Heng and Andrew Abell recently published a full paper in the journal ‘Organic and Biomolecular Chemistry’.

The published work presents three new spiropyran photoswitchable sensors and compares their sensitivity to different monovalent metal ions to develop a new reversible lithium ion sensor. These sensing molecules are now able to be further used to create optical devices for the sensing of biological lithium ions, which could help further understanding and treatment of neurological diseases such as manic-depressive illness.

Title: Crowned spiropyran fluoroionophores with a carboxyl moiety for the selective detection of lithium ions

Authors: D. B. Stubing, S. Heng and A. D. Abell

Abstract: The absorbance and fluorescence spectra of carboxylated spiropyrans containing methyl-1-aza-12-crown-4, methyl-1-aza-15-crown-5, methyl-1-aza-18-crown-6 moieties are compared. Characteristic changes in spectra after addition of the alkali metal salts of Li+, Na+, K+ and Cs+ were observed. Chromism induced by the binding of the metal cations was observed as an increase in absorbance and fluorescence. Of these metal cations, the Li+ ion produced the largest change in all three spiropyran systems. Reversible photoswitching of the spiropyran-metal complexes was observed on irradiation with alternating 352 nm UV and white light. This results in reversible fluorescence based sensing of lithium ions with potential for use in a biological sensor device.

The paper is accessible online.