Wyniki wyszukiwania - BazTech

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Polimery z odciśniętą cząsteczką - selektywne sorbenty do izolowania związków estrogennych

Sadowski R., Gadzała-Kopciuch R., Buszewski B.

Analityka : nauka i praktyka

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2014

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nr 2

4--8

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Sample preparation and HPLC determination of catechins in green tea

Blahova E., Lehotay J.

Chemia Analityczna

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2006

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Vol. 51, No. 5

795-807

EN

HPLC separation method of main seven green tea catechins has been developed. Three HPLC columns of different lengths, particle sizes, and sorbent properties were tested for this purpose. Separation was performed applying gradient elution with a mobile phase containing formic acid (0.28%) and an organic modifier (acetonitrile or methanol). Basic chroma-tographic characteristics were evaluated for each column and mobile phase composition. Extraction of catechins was performed in two ways: applying either methanol or boiling water under classical brewing conditions. Yields of analytes were calculated for both extraction techniques. Solid-phase extraction with molecularly imprinted polymer towards (+)-catechin was used for the cleanup of methanolic extract of green tea. Very good selectivity and recovery (95%) were achieved for the template molecule.

PL

Opracowano metodę rozdzielania siedmiu katechin herbaty zielonej za pomocą IIPLC. W tym celu zbadano 3 kolumny o różnej długości, wypełnione sorbentami o różnych właściwościach, w tym różniących się wielkością cząstek. Rozdzielanie prowadzono stosując elucje gradientową fazą ruchomą zawierającą kwas mrówkowy (0,28%) i modyfikator organiczny (acetonitryl lub metanol). Oceniono podstawowe charakterystyki chromatograficzne każdej kolumny i składu fazy ruchomej. Ekstrakcję katechin prowadzono dwoma sposobami - stosując wrzący metanol albo wodę w klasycznych warunkach zaparzania. Obliczano wydajność analitów dla obu technik ekstrakcji. Do oczyszczania metanolowego ekstraktu herbaty zielonej zastosowano ekstrakcję ciecz-cialo stałe z polimerem cząsteczkowo odwzo-rowanym względem (+)katechiny. Uzyskano bardzo dobra, selektywność i odzysk (95%) katechiny.

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Nowe wysoce selektywne sorbenty dla ekstrakcji ciecz-ciało stałe. Polimery z odwzorowanymi cząsteczkami

Mitrowska K., Posyniak A., Grzyb S.

Wiadomości Chemiczne

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2004

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[Z] 58, 3-4

277--291

EN

In the last few years solid-phase extraction (SPE) has become the most often used preconcentration technique for trace analysis. In SPE with most commercial sorbents, many components of complex samples are co-extracted, so additional clean-up is usually needed before the chromatographic analysis is made. However, specific SPE materials avoid this problem by providing a selective extraction. So far, the most selective phases used for SPE are based on immunoaffinity (IAC). The high selectivity and low stability of immunosorbents and the fact that is difficult and expensive to obtain biological antibodies are reason that IACs are used less widely for many different compounds [56, 57]. An alternative technology, using molecularly imprinted polymers (MIPs), is currently being extensively evaluated. Table 1 compares characteristics of molecularly imprinted polymer, immunoaffinity and conventional SPE columns. As depicted in Figure 1, MIPs are made in situ by copolymerization of functional monomeres and crosslinking monomeres in the presence of the print molecule, called the template that after extraction leaves its molecular impression on the surface as the polymer forms around it [39, 30]. The examples of most commonly used monomers are presented in Figure 2 and Figure 3, respectively. Table 2 provides an overview of examples of applications of SPE that incorporate molecularly imprinted polymer technology for extracting drugs and pollutants from different matrices. Besides SPE, MIPs have been applied as selective sorbents in several analytical techniques, including liquid chromatography [12-18], capillary electrophoresis, electrochromatography [19-23], as immunoassay and sensors [24-28].