Pyridine-2-aldehyde 2-furoylhydrazone as a fluorogenic reagent for the determination of nanogram amounts of gallium

Abstract

The synthesis, characteristics and analytical applications of pyridine-2aldehyde 2-furoylhydrazone (PAFH) are described. This compound has been examined to evaluate its usefulness as a selective and sensitive spectrofluorimetric reagent for gallium. The method is applied in 0.8% ethanolic solution a t p H 4.5. Under these conditions the fluorescent species have excitation and emission maxima at 380 and 445 nm, respectively. The detection limit is 0.8 ng ml-1 and the range of application is between 1 and 50 ng ml-l. The method has been employed to determine gallium in synthetic mixtures and its recovery from human urine samples.

Highly sensitive spectrofluorimetric determination of trace amounts of scandium with salicylaldehyde salicyloylhydrazone

“…In recent years, aroylhydrazones, which contain the group -CONHNNCH-, have been tested as fluorescent reagents. 1,2 The formation of complexes with a coplanar structure is conducive to the production of fluorescence: the reaction of a metal ion with a chelating agent induces rigidity in the resulting molecule and tends to produce fluorescence. 3 Scandium is found naturally with yttrium and the lanthanides in a variety of rocks and minerals.…”

“…In the recent literature, various methods for the determination of scandium have been proposed, several of which were spectrophotometric [1][2][3][4][5][6][7] or fluorimetric, [8][9][10][11][12][13] including the use of aroylhydrazones. Several separation procedures, such as fractional crystallization, liquid-liquid extraction and ion exchange, have been used to separate Sc from a large number of metal ions that form fluorescent and non-fluorescent complexes with organic reagents to quench the fluorescence of the scandium complex.…”