Mn. Church et al., TRANSIENT ISOTACHOPHORETIC-ELECTROPHORETIC SEPARATIONS OF LANTHANIDESWITH INDIRECT LASER-INDUCED FLUORESCENCE DETECTION, Analytical chemistry (Washington), 70(13), 1998, pp. 2475-2480
Indirect laser-induced fluorescence was used for the detection of seve
ral lanthanide species separated by capillary electrophoresis. Quinine
sulfate was the fluorescent component of the background electrolyte,
and alpha-hydroxyisobutyric acid was added as a complexing agent to en
able the separation of analyte ions that have similar mobilities. The
UV lines (333-364 nm) of an argon ion laser were used as the excitatio
n source with a diode array detector for monitoring the fluorescent em
ission at 442 nn. Electrokinetic injections and transient isotachophor
esis were implemented to stack the analyte ions into more concentrated
zones. On-line preconcentration factors were determined to be similar
to 700 and resulted in limits of detection for La3+, Ce3+, Pr3+, Nd3, Sm3+, and Eu3+ in the low-ppb range (6-11 nM).