CURRENT MEASUREMENT OF NONAQUEOUS SOLVENTS - APPLICATIONS TO CAPILLARY ELECTROPHORESIS AND ELECTROCHROMATOGRAPHY

The solvents acetonitrile, methanol, N,N-dimethylformamide, dimethyl s ulfoxide, formamide, and deionized water were investigated for their a bility to support current flow without added electrolyte, Using open t ubular capillary electrophoresis, currents were measured to be in the nanoampere (10(-9) A) range for all solvents but formamide (10(-6) A). Comparisons with flow data showed no clear relationship between curre nt and electroosmotic flow, Packed capillary columns (3-mu m ODS) were used for separations using both pure solvent and hydroorganic mixture s as mobile phases, Separation of four hydrophobic dyes showed mild re tention in pure ACN, A 16 polynuclear aromatic hydrocarbon (PAH) stand ard solution was separated in 80/20 ACN/H(2)0 with reduced plate heigh ts (h) between 2.8 and 3.1 for retained species. A separation of nine androstenediones was achieved using a 70/30 MeOH/H(2)0 mobile phase.