title: Separation of alkali metals using isotachophoresis with cryptand 222 as a leading electrolyte additive.
abstract: This work shows how the inclusion of cryptand 222 as a leading electrolyte additive in isotachophoresis affects the electrophoretic mobilities of alkali metal cations. Using isotachophoresis the separation of alkali metals can be difficult due to the similar electrophoretic mobilities of three of the ions: caesium, rubidium and potassium. However, the presence of cryptand 222 in the leading electrolyte retards the mobilities of the caesium, rubidium and potassium to a different extent allowing separations to be made. A novel electrolyte system was formulated which consisted of a leading electrolyte of 10 mM caesium hydroxide, 0.75 mM cryptand 222 buffered to pH 9.4 with glycylglycine and a terminating electrolyte of 10 mM tetrabutylammonium hydroxide. The use of this electrolyte system allowed good separations of mixtures of rubidium, potassium, sodium and lithium to be achieved. The method was also applied to the analysis of edible salt samples.
authors.affiliation: School of Chemical Engineering and Analytical Science, Manchester Institute of Biotechnology (MIB), The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK. j.prest@manchester.ac.uk
authors.forename: Jeff E
authors.initials: JE
authors.lastname: Prest
authors.forename: Peter R
authors.initials: PR
authors.lastname: Fielden
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Qi
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D057625:Isotachophoresis / Q000379:methods*; D008672:Metals, Alkali / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012492:Salts / Q000737:chemistry
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004573:Electrolytes; D008672:Metals, Alkali; D012492:Salts; C006071:cryptating agent 222