Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

A liquid chromatographic method for simultaneous determination of chlorophylls and carotenoids in fresh conifer needles

100%

Štěrbová D. , Klejdus B. , Kubáň V.

Chemia Analityczna

2003

tom Vol. 48, No. 2

233-241

A liquid chromatographic method for the separation of neoxanthin, violaxanthin, lutein, zeaxanthin, chlorophyll a, chlorophyll b, a-carotene and /J-carotene on the column Zorbax RX Cg (5 um, 150 x 2.1 mm I.D.) with photometric detection at 440 nm was optimized. An acetonitrile-water mixture, of a linearly increasing v/v ACN content (from 85% to 100% in 13 min and from 100% to 95% during the next 5 min) was used as a mobile phase. Its flow rate was established to 0.3 mL min'1 and the temperature of 20°C was set. Calibration curves were linear in the concentration ranges of 0.5-100 ng/inj. and 30-2600 ng/inj. for carotenoids and chlorophylls, respectively. Detections limits (LODs) in the range 0.1-0.5 ng/inj. and RSDs less than 1% (n = 5) were obtained. The results were compared with those obtained from dual-wavelength spectrophotometric measurements. The methods were applied to the determination of the concentration changes of the pigments in fresh conifer needles of bristlecone pine (Pinus aristata, Engellman) during eclipse on August 11,1999.

Zoptymalizowano metodę chromatografii cieczowej do rozdzielania, neoksantyny, wiolaksantyny, luteiny, zeaksantyny, chlorofilu a, chlorofilu b, a-karotenu and ^3-karotenu przy użyciu kolumny Zorbax RX Cg (5 um, 150 x 2.1 mm I.D.) z detekcją fotometryczną przy długości fali 440 nm. Jako fazę ruchomą zastosowano mieszaninę acetonitrylu i wody. Liniowy gradient składu wynosił od 85% do 100% acetonitrylu w ciągu 13 min oraz od 100% do 95% acetonitrylu w ciągu następnych 5 min, szybkość przepływu 0,3 mL min(-1), temp. 20°C. Wykresy kalibracyjne były liniowe w zakresie stężeń (w próbkach zadozowanych) 0,5-100 ng i 30-2600 ng odpowiednio dla karotenoidów i chlorofili.

Assessment of antioxidants by HPLC-MS in grapevine seeds

63%

Sochorova L. , Klejdus B. , Mojmir B. , Tunde J. , Mlcek J. , Sochor J. , Ercisli S. , Kupe M.

nr 6

It is well known, that grapevine seeds are rich in significant antioxidants. However, the issue of dealing with the analysis and comparison of antioxidant components in the seeds of Vitis vinifera L. in individual cultivars has not yet been sufficiently studied. The experiment was performed with extracts of three varieties (Blaufränkish, Italian Riesling and Cabernet Moravia) and three interspecific cultivars (Nativa, Marlen and Kofranka). Contents of nine major flavonoids (apigenin, astragalin, hyperoside, isorhamnetin, kaempferol, myricetin, quercetin, quercitrin and rutin) and two procyanidins (procyanidin A2 and procyanidin B1) were assessed by the HPLC/MS method. The highest contents of antioxidants were found out in interspecific cultivars Marlen and Nativa while the lowest one was assessed in the cultivar Cabernet Moravia. The most represented flavonoid was hyperoside (cultivar Marlen – 15.66 mg∙l–1), least represented was kaempferol (cultivar Cabernet Moravia – 1.81 µg∙l–1).