Specific Fluorescence Detection of Lithium Ion using Quinizarin and Extraction in TBP

Abstract
A simple and specific spot-test for lithium based on a fluorescent reaction betwen Li+ ion and Quinizarin in alkaline medium is described. The resulting compound is extracted in TBP, and fluorescence is observed in the organic phase under illumination with a UV lamp at 360 nm. The sensitivity of the test is 0.1 μg.cm−3. Applications of the test for lithium include the corresponding cation groups using the H2S and Na2CO3 systematic schemes of analysis; and directly in synthetic mixtures of inorganic ions, mineral water, drugs, dietetic products and blood serum.