Separation and sensitive detection of lanthanides by capillary electrophoresis and contactless conductivity detection

Abstract

A rapid and sensitive capillary zone electrophoresis method for the simultaneous separation and determination of lanthanide ions, combined with capacitively coupled contactless conductivity detection (C4D), is reported. The influence of experimental parameters on separation was investigated. The optimal separation conditions were obtained when 4.5mM 2-hydroxyisobutyric acid and 1mM acetic acid (HAc) at pH 4.5 were used as buffer solution. Under these conditions, complete separation of all 14 lanthanide ions was achieved in 6 min. With the use of the C4D detector, the sensitive detection of non-UV active lanthanide ions was achieved without the need of a UV active ligand or a visualization agent. The sensitivities were further enhanced with a sample stacking procedure. The limits of detection were to be found between 2.77 and 8.26 nmol/L and the limits of quantification were between 9.29 and 27.5 nmol/L for 14 lanthanide ions.