Ya. Ibrahim et al., Seventeen new 14- and 15-crown-formazans: their synthesis and evaluation in spectrophotometric determination of lithium, TALANTA, 47(5), 1998, pp. 1199-1213
A number of new crown-formazans with 14 and 15 membered rings have been syn
thesized, characterized and investigated as selective spectrophotometric ch
elating agents for lithium. The effect of sodium ion concentration on the b
ackground lithium signal was studied. A comparative study for the sensitivi
ty of these new crown-formazans in spectrophotometric determinations was st
udied and compared with those reported previously. The three new 14- and 15
-crown-formazans 4a-c containing the pyridyl N-oxide at the formazyl carbon
showed the highest selectivity to lithium determination in the presence of
sodium ion. (C) 1998 Elsevier Science B.V. All rights reserved.