title: On-line coupling of Micro-Extraction by Packed Sorbent with Sequential Injection Chromatography system for direct extraction and determination of betaxolol in human urine.
abstract: A novel approach for automation of Micro-Extraction by Packed Sorbent (MEPS), a solid phase extraction technique, is presented, enabling precise and repeatable liquid handling due to the employment of sequential injection technique. The developed system was used for human urine sample clean-up and pre-concentration of betaxolol before its separation and determination. A commercial MEPS C-18 cartridge was integrated into an SIChrom™ system. The chromatographic separation was performed on a monolithic High Resolution C18 (50×4.6 mm) column which was coupled on-line in the system with Micro-Extraction using an additional selection valve. A mixture of acetonitrile and aqueous solution of 0.5% triethylamine with acetic acid, pH adjusted to 4.5 in ratio 30:70 was used as a mobile phase for elution of betaxolol from MEPS directly onto the monolithic column where the separation took place. Betaxolol was quantified by a fluorescence detector at wavelengths λ(ex)=220 nm and λ(em)=305 nm. The linear calibration range of 5-400 ng mL(-1), with limit of detection 1.5 ng mL(-1) and limit of quantification 5 ng mL(-1) and correlation r=0.9998 for both the standard and urine matrix calibration were achieved. The system recovery was 105±5%; 100±4%; 108±1% for three concentration levels of betaxolol in 10 times diluted urine - 5, 20 and 200 ng mL(-1), respectively.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague, Heyrovského 1203, Hradec Králové 50005, Czech Republic.
authors.forename: Ivana
authors.initials: I
authors.lastname: Šrámková
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague, Heyrovského 1203, Hradec Králové 50005, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Chocholouš
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague, Heyrovského 1203, Hradec Králové 50005, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Sklenářová
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague, Heyrovského 1203, Hradec Králové 50005, Czech Republic. Electronic address: satinsky@faf.cuni.cz.
authors.forename: Dalibor
authors.initials: D
authors.lastname: Šatínský
mesh_terms: D015784:Betaxolol / Q000302:isolation & purification* / Q000652:urine*; D002845:Chromatography / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007267:Injections; D008297:Male; D052617:Solid Phase Microextraction / Q000379:methods*; D013050:Spectrometry, Fluorescence; D016482:Urinalysis / Q000295:instrumentation / Q000379:methods*
chemical_list: D015784:Betaxolol
keywords: Automation; Betaxolol; Fluorimetry; Liquid chromatography; Micro-Extraction by Packed Sorbent (MEPS); Sequential Injection Chromatography (SIC)