NOVEL ELECTROLYTE FOR THE ANALYSIS OF CATIONS IN LOW EXPLOSIVE RESIDUE BY CAPILLARY-ELECTROPHORESIS

A novel electrolyte has been developed for the effective separation by capillary electrophoresis of cations detected in low explosive residu e. This electrolyte, with a pH of 4.4, employs 17.5 mM alpha-hydroxyis obutyric acid (HIBA) as the complexing agent, 6 mM imidazole as the ul traviolet visualization agent, 4 mM 18-crown-6 ether as a modifier to enhance the selectivity of the inorganic cations, and 5% (v/v) acetoni trile as an organic additive. Studies which assessed the value of the addition of 18-crown-6 and acetonitrile demonstrated conclusively that both were required in order to achieve unambiguous baseline separatio n of ammonium, potassium and monomethylammonium ions. The major advant ages of the use of this electrolyte are a total run time of less than 7 min and symmetrical peak shapes. Validation on a series of preblast and postblast explosives materials determined that this procedure is r eliable and robust. (C) 1998 Elsevier Science B.V. All rights reserved .