title: Creatinine determination in serum by capillary electrophoresis.
abstract: Creatinine in human serum was separated in a fused-silica capillary with H3PO4 (75 mmol/L, pH 2.5) as BGE, followed by UV detection at 200 nm. Serum with methylimidazole added as internal standard was deproteinized with acetonitrile and the supernatant, after dilution with water was injected at pressure mode. Creatinine and methylimidazole were baseline-resolved in 6.5 min. Linearity in the 0-880 micromol/L range gave an r2 > or = 0.998, recovery was 102 +/- 2.8% (n = 6). Enzymatic breakdown with creatininase confirmed that serum does not interfere. The within-day and between-days coefficient of variation (CV) were < or = 2.16 and 2.7%, respectively. The accuracy, determined for lyophilized samples by isotope dilution gas chromatography-mass spectrometry was < or = +/- 2.0%. The results were compared with HPLC for 32 lyophilized samples and on 27 serum pools. Capillary electrophoresis, rapid and inexpensive, seems a promising alternative to high-performance liquid chromatography (HPLC) for creatinine determination in human serum.
authors.affiliation: Lab. Separative Techniques, IRCSS H San Raffaele, Milan, Italy. rata.paroni@unimi.it
authors.forename: Rita
authors.initials: R
authors.lastname: Paroni
authors.forename: Isabella
authors.initials: I
authors.lastname: Fermo
authors.forename: Giuliana
authors.initials: G
authors.lastname: Cighetti
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Ferrero
authors.forename: Anna
authors.initials: A
authors.lastname: Carobene
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Ceriotti
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000097:blood*; D019075:Electrophoresis, Capillary / Q000379:methods*; D005612:Freeze Drying; D006801:Humans; D007093:Imidazoles; D010756:Phosphoric Acids
chemical_list: D007093:Imidazoles; D010756:Phosphoric Acids; C029899:imidazole; D003404:Creatinine; C030242:phosphoric acid