Browsing by Author "Hakova Martina"

Now showing 1 - 6 of 6
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    A comparison study of nanofiber, microfiber, and new composite nano/microfiber polymers used as sorbents for on-line solid phase extraction in chromatography system
    (Elsevier Ltd., 2018-01-01) Hakova Martina; Chocholousova Havlikova Lucie; Chvojka Jiří; Erben Jakub; Solich Petr; Švec František
    Three different approaches has been used to obtain nano/micro fibers and their diversity and extraction properties were examined. The effect of their structure on stability in an ultra-high-performance liquid chromatography (UHPLC) system during on-line SPE procedure was monitored. Five types of various nano/micro fiber polymers were used as sorbents: polyamide 6 nanofibers, polyvinylidene difluoride nanofibers, polyethylene microfibers, and two new polycaprolactone microfiber/nanofiber and polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite polymers. The fiber polymers were filled in a cartridge directly connected to the UHPLC system and tested. For each polymer, the optimal conditions of the on-line extraction were found and potential applicability on real samples was tested. The determination of ochratoxin A (OTA) in beer matrix was chosen as a case study. Relevant factors such as the mechanical and chemical stability of the nano/microfibers, filling the cartridges, fiber reusability and the possibility and the repeatability of all processes were involved in the proposed study. A new nano/micro composite sorbent consisting of polycaprolactone microfibers/polyvinylidene difluoride nanofibers was chosen as the most suitable sorbent for the on-line extraction of OTA from a beer matrix. The tested validation parameters had the value of intra-day precision lower than 1.48%, linearity in the range from 0.5 to 100 μg L−1 with r2 ≥ 0.9999 for standard and matrix calibration curve, and recovery in the range 99.1–103.9% at five concentration levels. Long-term precision evaluated for 31 analyses over the period of three months did not exceed 2.9% RSD. It confirmed the column reusability and perfect stability of nano/micro composite sorbent in the presence of organic solvents and after repeated injection of a complex beer matrix.
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    Nanofiber polymers as novel sorbents for on-line solid phase extraction in chromatographic system: A comparison with monolithic reversed phase C18 sorbent
    (Elsevier Ltd, 2018-01-01) Hakova Martina; Chocholousova Havlikova Lucie; Chvojka Jiří; Švec František; Solich Petr; šatinský Dalibor
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    New Polyamide 6 Nanofibrous Sorbents Produced Via Alternating Current Electrospinning For The On-Line Solid Phase Extraction Of Small Molecules In Chromatography Systems
    (Elsevier, 2021-01-01) Erben Jakub; Klíčová Markéta; Klápšťová Andrea; Hakova Martina; Lhotská Ivona; Zatrochová Slavomíra; Šatínský Dalibor; Chvojka Jiří
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    An on-line coupling of nanofibrous extraction with column-switching high performance liquid chromatography: A case study on the determination of bisphenol A in environmental water samples
    (2018-01-01) Hakova Martina; Chocholousova Havlikova Lucie; Chvojka Jiří; Solich Petr; šatinský Dalibor
    Polyamide 6 nanofiber polymers were used as modern sorbents for on-line solid phase extraction (SPE) coupled with liquid chromatography. The on-line SPE system was tested for the determination of bisphenol A in river water samples. Polyamide nanofibers were prepared using needleless electrospinning, inserted into a mini-column cartridge (5 × 4.6 mm) and coupled with HPLC. The effect of column packing and the amount of polyamide 6 on extraction efficiency was tested and the packing process was optimized. The proposed method was performed using a 50-µL sample injection followed by an on-line nanofibrous extraction procedure. The influence of the washing mobile phase on the retention of bisphenol A during the extraction procedure was evaluated. Ascentis® Express C18 (10 cm × 4.6 mm) core-shell column was used as an analytical column. Fluorescence detection wavelengths (λex = 225 nm and λem = 320 nm) were used for identification and quantification of Bisphenol A in river waters. The linearity was tested in the range from 2 to 500 µg L−1 (using nine calibration points). The limits of detection and quantification were 0.6 and 2 µg L−1, respectively. The developed method was successfully used for the determination of bisphenol A in various samples of river waters in the Czech Republic (The Ohře, Labe, Nisa, Úpa, and Opava Rivers).
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    On-line polydopamine coating as a new way to functionalize fibrous sorbent for solid phase extraction
    (Elsevier, 2020-01-01) Hakova Martina; Chocholouš Petr; Valachovič Adam; Erben Jakub; Chvojka Jiří; Solich Petr; Švec František; Šatínský Dalibor
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    Poly-&epsi-caprolactone Nanofibrous Polymers: A Simple Alternative to Restricted Access Media for Extraction of Small Molecules from Biological Matrixes
    (ACS Publications, 2020-01-01) Raabová Hedvika; Hakova Martina; Chocholousova Havlikova Lucie; Erben Jakub; Chvojka Jiří; Solich Petr; Švec František; Šatínský Dalibor