P. Solich et al., FLOW-INJECTION DETERMINATION OF VARIOUS COUMARINS IN A MIXTURE BY MEANS OF DIFFERENTIAL FLUOROMETRY, Die Pharmazie, 50(8), 1995, pp. 545-547
A differential-fluorimetric flow-injection determination of scopoletin
e or umbelliferone in binary mixtures with herniarine based on the pH-
dependence of the fluorescence spectra of the analytes is described. A
simple flow system involving a double-injection valve for the simulta
neous introduction of a buffer and a sample plug into a carrier, and a
flow-through fluorimetric detector is used. Two variants of the metho
d enable the determination of greater than or equal to 1 mu mol . l(-1
) of scopoletione or umbelliferone in the presence of less than or equ
al to 100-fold molar excess of herniarine. The procedure was applied t
o the determination of umbelliferone and herniarine in a commercial ph
armaceutical preparation.