Capillary ion electrophoresis of inorganic cations in standard reference materials from vegetable source

Taking into account the growing interest in applying capillary ion electrop horesis (CIE) for the determination of inorganic ions in real samples, this work focuses on CIE analysis of K+, Na+, Ca2+, Mg2+, and Mn2+ in botanical and food reference materials. Microwave-Assisted Digestion for sample preparation has been chosen ensurin g a rapid, accurate, and reproducible treatment. A fused-silica capillary, 75 mu m x 60 cm, a background electrolyte consisting of 6 mM imidazole and 10 mM alpha-hydroxy-isobutyric acid (HIBA). and indirect UV detection at 21 4 nm were used. Certified reference materials as Apple leaves SRM 1515 (NIST, USA), Beech l eaves CRM 100, Rye flour CRM 381, Haricot beans CRM 383, and the green alga e Ulva lactuca CRM 279 (BCR, Belgium) were selected. The optimal experiment al conditions for microwave digestion and operational parameters in the ele ctrophoresis system were studied. The calibration curves for K, Ca, Mg, and Mn ions were linear over the rang e of 0.6 ppm to 120 ppm and the detection limits (CLOD) were between 0.05 p pm and 0.20 ppm depending on the ions analyzed. Accuracy and precision with in and between days were determined. The results were in good agreement wit h those reported in certified materials acid they were also comparable with those obtained by atomic absorption and emission spectrometry.