Quercetin- and morinsulfonates as analytical reagents

Sulfonate derivatives of quercetin and morin, quercetin-5'-sulfonic acid (QSA) and sodium morin-5'-sulfonate (NaMSA), form complexes with p, d-, and f-electron metal ions in solution and a solid state similarly to quercetin and morin. QSA and NaMSA are well-soluble in water, contrary to quercetin and morin. Metal ion complexes of QSA and MSA have high absorption coefficients of 10(4) L-3 mol(-1) cm(-1). Therefore, those complexes can be conveniently used for the spectrophotometric determination of metal ions. Moreover, some of complexes reveal strong luminescence and can be applied to spectrofluorimetric analysis.