title: Capillary isotachophoresis of cystine in urine with on-line isotachophoresis sample pretreatment.
abstract: Capillary isotachophoresis (ITP) with on-line isotachophoresis sample pretreatment and conductivity detection has been proposed as a method for the separation, detection and determination of cystine present in urine. Sample pretreatment was achieved using a 90 mm FEP capillary tube with a 800 microm internal diameter. ITP separations and conductivity detection were carried out in a 160 mm capillary tube with a 300 microm internal diameter, filled with a hydrochloric acid leading electrolyte and glycine terminating electrolyte, at 50 microA and 25 degrees C. The results show that the proposed method is suitable for resolution of cystine from matrix interferents present in the urine samples and is able to detect it at 10(-4) mol/l concentrations by a universal detection technique after removal of a significant part of the anionic constituents of the sample migrating in the on-line coupled capillary isotachophoresis stack. This simple ITP procedure for monitoring cystine in urine samples requires no sample preparation. This makes it an alternative to the currently used procedures.
authors.affiliation: Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovakia. mikuspeter@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Mikus
authors.forename: P
authors.initials: P
authors.lastname: Kubacák
authors.forename: I
authors.initials: I
authors.lastname: Valásková
authors.forename: E
authors.initials: E
authors.lastname: Havránek
mesh_terms: D000328:Adult; D003553:Cystine / Q000032:analysis*; D004563:Electrochemistry; D004573:Electrolytes; D019075:Electrophoresis, Capillary; D006801:Humans; D007202:Indicators and Reagents; D009862:Online Systems; D015203:Reproducibility of Results
chemical_list: D004573:Electrolytes; D007202:Indicators and Reagents; D003553:Cystine