Determination of ascorbic acid in isolated pea plant cells by capillary electrophoresis and amperometric detection

A capillary electrophoretic method for the determination of ascorbic acid i n a single protoplast, i.e., a plant cell without cell wall, has been devel oped. Amperometric detection using a carbon fibre disc electrode at 1.0 V v s. Ag/AgCl was applied. The running buffer consisted of 10 mM phosphate, pH 7. The limit of detection was approximately 5 mu M for measurements on sin gle protoplasts, typically 20 mu m in diameter, and 22 nM for measurements with ascorbic acid standard solutions. The concentration of ascorbic acid v aried between 0.05 and 1.6 mM for five selected, isolated and injected prot oplasts. (C) 1998 Elsevier Science B.V. All rights reserved.