ABSTRACT
For the enhancement of sample loadability and concentration sensitivity in capillary zone electrophoresis/mass spectrometry (CZE/MS) on-line isotachophoresis/capillary zone electrophoresis (ITP/CZE) in a single capillary prior to mass spectrometric detection is described for clenbuterol and some analogues. Concentration detection limits were found to be in the nanogram per millilitre range. The applicability of ITP/CZE/MS as a trace analysis technique is demonstrated by the determination of some beta-agonists in calf urine.
Subject(s)
Adrenergic beta-Agonists/urine , Animals , Cattle , Drug Residues/analysis , Electrophoresis , Mass SpectrometryABSTRACT
A rapid method for the determination of daunorubicin, doxorubicin and epirubicin in human plasma is described. Samples are pretreated and concentrated by liquid-liquid extraction with chloroform and back-extraction into phosphoric acid, respectively. This pretreatment results in a sample matrix of low ionic strength in comparison with the electrophoresis buffer, permitting a 20-30-fold increase in the injected amount by zone sharpening when electrokinetic injection is applied. Analyte interaction with the capillary wall is prevented by using high acetonitrile contents in the electrophoresis buffer, which results in reproducible migration times and highly efficient separations. Laser-induced fluorescence detection provides an extremely sensitive and selective method without detectable biological interferences. The limit of determination of daunorubicin, epirubicin and doxorubicin in plasma ranges from 125 to 250 pg/ml.
Subject(s)
Daunorubicin/blood , Doxorubicin/blood , Epirubicin/blood , Electrophoresis/methods , Humans , Lasers , Reproducibility of Results , Spectrometry, FluorescenceABSTRACT
An array detection system based on position- and time-resolved ion counting was evaluated for capillary electrophoresis-mass spectrometry using continuous-flow fast atom bombardment and a liquid-junction coupling. Peptides with molecular masses up to 3200 were measured. A 100-1000-fold improvement over conventional detection was demonstrated by applying the array detector in scanning and static modes. Absolute detection limits in the range 1-5 fmol are achievable.
