title: Evaluation of sample injection precision in respect to sensitivity in capillary electrophoresis using various injection modes.
abstract: A comparative study was conducted to assess the injection precision in capillary electrophoresis for cationic analytes (arecoline, codeine, papaverine). The precision was measured in respect to methods sensitivity in various injection modes in capillary electrophoresis: standard hydrodynamic injection (3.45 kPa for 6 s), large volume sample stacking (3.45 kPa for 40 s), and field-amplified sample injection (10 kV for 65 s). All measurements were conducted for aqueous solutions of standards to minimize the errors linked to the sample preparation step. The methods were submitted to precision assessment at three concentration levels: at the limit of quantification, three-fold and ten-fold of limit of quantification. The results were compared to those from high-performance liquid chromatography as a reference technique. The field-amplified sample injection method was shown to provide greatest sensitivity (quantification limits down to 4 ng/mL for all three tested compounds) but the lowest precision. High-performance liquid chromatography was established as the most reliable technique (coefficient of variation in all intraday experiments was below 1%). It was also shown that with a use of large volume sample injection technique, similar sensitivity as in high-performance liquid chromatography can be easily reached.
authors.affiliation: Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Krzesimir
authors.initials: K
authors.lastname: Ciura
authors.affiliation: Department of Toxicology, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Pawelec
authors.affiliation: Department of Biopharmaceutics and Pharmacodynamics, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Buszewska-Forajta
authors.affiliation: Department of Biopharmaceutics and Pharmacodynamics, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Michał Jan
authors.initials: MJ
authors.lastname: Markuszewski
authors.affiliation: Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Nowakowska
authors.affiliation: Institute of Organic Synthesis, Department of Organic Chemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Prahl
authors.affiliation: Department of Toxicology, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Wielgomas
authors.affiliation: Department of Toxicology, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Szymon
authors.initials: S
authors.lastname: Dziomba
keywords: capillary electrophoresis; liquid chromatography; repeatability; sensitivity; stacking