Trace determination of lanthanum,cerium, and praseodymium based on adsorptive stripping voltammetry

A sensitive stripping procedure is described for quantifying lanthanum, cerium and praseodymium ions, based on the controlled adsorptive accumulation of the lanthanide/o- cresolphthalexon complex onto the static mercury drop electrode. The effect of various operational parameters on the stripping response is discussed. A 20-min accumulation period coupled with differential pulse measurement of the current resulting from the adsorbed complex permits quantitation down to the 1 × 10^?10 M level. For concentrations ranging from 2.5 × 10^?8 M to 2.5 × 10^?9 M, a 0.5- to 4-min accumulation period is sufficient. The relative standard deviation ar the 7 × 10^?8 M level ranges from 1 to 6%.