On-line solid phase extraction-capillary electrophoresis for the simultaneous determination of Rare Earth Elements at sub-ppm levels

CERUTTI S; GILL R; MARTINEZ LD; VIZIOLI NM; SILVA MF

Guarujá, Brasil

Simposio; 11th Symposium on Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technology, LACE 2005; 2005

Modern analytical chemistry is characterized by hyphenated analytical methods that involve a Combination of a separation and/or sensitive detection technique with a preconcentration step. The latter is a consequence of the problems encountered in the chemical analysis of complex analytical samples, such as low analyte concentrations (in many cases incompatible with quantification limits of modern instrumental methods) and high concentrations of matrix interference species present in these complex samples, especially those with biological or environmental origin. During the past two decades, capillary electrophoresis and related techniques have moved to the forefront of analytical chemistry and have excelled in the rapid analysis of ions, replacing traditional separation methods. Metal analysis by CE has the advantages of robustness and ruggedness, low cost, rapidness, and versatility. However, CE suffers from poor concentration sensitivity when using UV detection because of the small sample introduction and narrow optical path length. Consequently, there is a continuing need for the development of alternative extraction/enrichment procedures that are safe, rapid, convenient, and accurate. The aim of the present work is to evaluate the feasibility of coupling an on-line preconcentration step to CE for the simultaneous determination of metal ions at ultra-trace levels. Two different preconcentration strategies are presented and evaluated: cloud point extraction (CPE) and solid-phase microcolumn (SPME) and their applications to different environmental, clinical, geological, and food samples. Strategies for method development as well as future perspectives are also covered.