Analysis of alkaloids in single plant cells by capillary electrophoresis

In this chapter, capillary electrophoresis (CE) is demonstrated to be a useful technique for the determination of alkaloids in microsamples of single plant cells. A single cell sampling technique with microcapillaries that includes extraction of sample volumes in the pl range from single cells, division into aliquots, addition of internal standard, and injection into the CE capillary is described. The danger of contamination and evaporation of such low sample volumes has been avoided by handling them under an inert protective layer of silicone oil. For the determination of alkaloids in cell samples, CE with direct ultraviolet detection using a high concentration of citric acid as background electrolyte provides sufficient sensitivity.