Selective spectrofluorometric determination of lithium(I) with quinizarin by extraction into tributyl phosphate.
A method for the determination of trace amounts of lithium at the ppb level has been described based on the reaction of lithium(I) with 1,4-dihydroxyanthraquinone (quinizarin) in alkaline medium, extraction into tributyl phosphate (TBP) and measurement of the fluorescence of the organic phase. A linear calibration was found in the concentration range of 9-250 ppb of lithium in aqueous solutions (lambda(exc)=590 nm, lambda(em)=670 nm) with a RSD of 2.7% for 100 ppb of lithium. After a prior treatment with potassium carbonate the method is highly specific for the analysis of lithium in presence of other inorganic ions. The proposed procedure has been applied for the determination of lithium in mineral waters, drugs and vegetables.
Rodríguez
L C
LC
Department of Analytical Chemistry Faculty of Sciences, University of Granada, Avda. Fuentenueva s.n., E-18071, Granada, Spain.
Linares
C J
CJ
Ceba
M R
MR