title: On-line SPE-CE for the determination of insulin derivatives in biological fluids.
abstract: An on-line SPE-CE system is described for the determination of insulin derivatives in urine, serum and plasma. By combining techniques based on different separation mechanisms, in this case reversed-phase SPE and CE, a more selective sample clean-up is obtained. The described on-line SPE-CE procedure is able to desalt and clean biological samples, resulting in more repeatable electrophoretic results as well as a good linearity for urine, serum and plasma samples spiked with insulin derivatives, thus proving the elimination of detrimental effects caused by the sample matrix. The on-line SPE-CE system was linear for urine, serum and plasma samples spiked with insulin derivatives between 5 and 80 mg/l. The repeatability in migration time was below 1% relative standard deviation (R.S.D.). The repeatability of the peak was better (<2.4% R.S.D.) when no off-line precipitation reaction (<6.2% R.S.D.) was used, proving the beneficial characteristics of on-line sample pretreatment procedures over off-line sample pretreatment procedures which are prone to sample losses and contamination.
authors.affiliation: Division of Chemistry, Analytical Chemistry and Applied Spectroscopy, Faculty of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam, Netherlands.
authors.forename: N F C
authors.initials: NF
authors.lastname: Visser
authors.forename: M
authors.initials: M
authors.lastname: van Harmelen
authors.forename: H
authors.initials: H
authors.lastname: Lingeman
authors.forename: H
authors.initials: H
authors.lastname: Irth
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001826:Body Fluids / Q000737:chemistry*; D002417:Cattle; D019075:Electrophoresis, Capillary / Q000379:methods; D006801:Humans; D007328:Insulin / Q000032:analysis* / Q000235:genetics*; D008969:Molecular Sequence Data; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D007328:Insulin