Chemistry Letters, Vol.30, No.4, 302-303, 2001
Retention selectivity between 4-(2-pyridylazo)resorcinol and its cobalt chelate in the solid phase extraction systems and its application to the on-line preconcentration for reversed phase HPLC
Preferential solid phase extraction of ultratrace metal chelate from the excess of its ligand has been succeeded in the case of cobalt, 4-(2-pyridylazo)resorcinol (PAR), ODS-Silica, and H2O system, applying the reverse order of them found in reversed-phase HPLC with aqueous methanol and ODS-SiO2. This finding makes it possible to concentrate the 1-ppt level of cobalt chelate in the presence of excess PAR from aqueous samples using kinetically selective HPLC.