title: Capillary electrophoresis of trace metals in highly saline physiological sample matrices.
abstract: Trace metal ions in highly saline samples such as urine were determined with capillary electrophoresis (CE) without desalting or off-line preconcentration. By mixing with a dye, 4-(2-pyridylazo) resorcinol (PAR), the metal ions were converted into anionic complexes having strong absorbance near 500 nm. A large volume of the metal-PAR complex sample solution injected into a coated capillary was stacked isotachophoretically and separated under a reverse potential. The salt anion (chloride) and PAR in the sample matrix acted as the leading and terminating electrolytes, respectively. In a sample containing a 250 mM NaCl matrix, more than 400-fold enhancement in the absorbance detector response was realized compared to the normal CE injection mode. Combination of the dye complexation and isotachophoretic stacking provided excellent detection limits (S/N = 3) for three trace metal ions in the low ppb range (Fe(2+), 0.7 ppb, Ni(2+), 0.4 ppb; Zn(2+), 1.2 ppb) with absorbance detection. The migration time reproducibility was excellent (relative standard deviations: standard samples < 1%, urine samples approximately 1%). The proposed method is convenient and fast, and the sample analysis can be completed within 20 min.
authors.affiliation: School of Chemistry, Seoul National University, Seoul 151-747, Korea.
authors.forename: Asif
authors.initials: A
authors.lastname: Riaz
authors.forename: Bojeong
authors.initials: B
authors.lastname: Kim
authors.forename: Doo Soo
authors.initials: DS
authors.lastname: Chung
mesh_terms: D000818:Animals; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007501:Iron / Q000032:analysis; D009532:Nickel / Q000032:analysis; D012492:Salts; D012965:Sodium Chloride; D014131:Trace Elements / Q000032:analysis* / Q000652:urine; D015032:Zinc / Q000032:analysis
chemical_list: D012492:Salts; D014131:Trace Elements; D012965:Sodium Chloride; D009532:Nickel; D007501:Iron; D015032:Zinc