Wyniki wyszukiwania - Biblioteka Nauki

1

Optimization of determination of reduced and oxidized glutathione in rat striatum by HPLC method with fluorescence detection and pre-column derivatization

100%

Gawlik M. , Krzyżanowska W. , Gawlik M. B. , Filip M.

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tom Vol. 26, no. 2

335--345

EN

A high-performance liquid chromatography (HPLC) method was used to assess the concentration of reduced and oxidized glutathione (GSH and GSSG) in rat striatum. Following decapitation, striatum was isolated from the male Wistar rat brain and immediately homogenized with double distilled water. GSH level was determined after pre-column derivatization with o-phthalaldehyde (OPA). The optimal incubation time with OPA was tested. The concentration of GSSG was determined after blockage the thiol groups of GSH by N-ethylmaleimide (NEM). The useful time for incubation with NEM was optimized. Next, disulfide bounds of GSSG were reduced by dithiothreitol (DTT), and released GSH is derivatized with OPA. The total glutathione, tGSH (sum of free and bound GSH, GSSG, and other low-molecular-mass aminothiols), was determined after reduction with DTT and then derivatization with OPA. The level of GSSG was calculated of the difference in concentrations of tGSH and GSH, but we showed that the calculated concentration of GSSG was within the range of standard deviation of the mean concentration of tGSH or GSH. Finally, the concentration of GSH was determined after 5-min incubation with OPA and the concentration of GSSG after 30-s incubation with NEM and 5-min incubation with DTT and OPA. The relative standard deviation (RSD) values obtained for the assay of GSH and GSSG were lower than 10%. The values obtained for accuracy for GSH (50–500 nM) and GSSG (0.5–5 nM) were within limits regarded as acceptable for analysis of biological samples (percent of recovery: 95–105%). Mean absolute recovery of GSH and GSSG was ranged from 97.1% to 99%. Limit of detection for GSH was 2.7 nM, and limit of quantification was 8.2 nM. Limit of detection (LOD) for GSSG is twice the value for GSH. Described method allows to determine GSH and GSSG levels in isolated rat brain structures with high level of reliability.

2

Changes in phytoplankton pigments composition during 2000 in different southern Baltic regions

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Ston J. , Kosakowska A.

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2002

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tom Vol. 31, No. 1-2

75-89

EN

The results of differences in phytoplankton pigments composition are presented in this paper. Samples from the Southern Baltic taken during three cruises on r/v "Oceania" (14.02 - 28.02.2000, 06.05 - 16.05.2000 and 20.09 - 01.10.2000) were examined. Qualification and quantification analyses of chlorophylls and carotenoids present in samples of naturally existing phytoplankton were based on the RP-HPLC technique. Seasonal and spatial variability in pigment characteristics was observed in the analysed seasons. Presence of: chlorophyll a, chlorophyll c1+c2, chlorophyll b, alloxanthin, zeaxanthin, fucoxanthin, peridinin, neoxanthin, diadinoxanthin - was noted in every season; violaxanthin and beta-carotene - only in May and September. Lutein was detected only in May samples. The quantity of May and September pigments exceeded 2-6 times the February pigments content. Vertical differentiation in the pigments amount was also noted. Spatial variability emphasized the influence of Vistula and Odra water masses. Different markers of phytoplankton species were found in each season: in February - cryptophytes (alloxanthin), May - diatoms (fucoxanthin) and September - cyanophytes and dinophytes (containing zeaxanthin and diadinoxanthin).

3

An HPLC method for the determination of the anticancer complex 3-hydroxycarboplatin

100%

Yang S. , Chen X. , Zhen P. , Ye Q. , Xie X. , Liu W.

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tom Vol. 23, no. 4

539--550

EN

A simple and rapid HPLC method using a photodiode array (PDA) detector for the analysis of 3-hydroxycarboplatin and its related complex has been established for the first time. Separation of 3-hydroxycarboplatin and 3-hydroxy-1,1-cyclobutanedicarboxylic acid (3-HO-cbdca) was carried out on a Phenomenex ODS3 column using an aqueous solution containing 50 mM ammonium acetate and 5 mM sodium 1-octanesulfonate as the mobile phase. The flow rate was 0.8 mL min-1, the column temperature was 40°C, and the detection wavelength was 230 nm for 3-hydroxycarboplatin and 220 nm for 3-HO-cbdca. Different analytical performance parameters such as precision, accuracy, linearity, stability of the solution, specificity, limit of detection (LOD), limit of quantification (LOQ), and system suitability were determined using the Empower 2 software. The calibration curve of standard 3-hydroxycarboplatin showed good linearity (r = 0.9995) within the range 0.5–1.4 mg mL-1. The method was accurate and precise, with an average accuracy of 100.4% (RSD = 1.53%, n = 9), and the results of the system suitability test showed symmetrical peaks, good resolution (Rs), and repeatability. It can be applied to the quality control of 3-hydroxycarboplatin.

4

Simultaneous separation of chlorophylls and carotenoids by RP-HPLC in some algae and cyanobacteria from the southern Baltic

75%

Jodłowska S. , Latała A.

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tom Vol. 32, No. 2

81-89

EN

RP-HPLC (reversed-phase high-performance liquid chromatography) was used to analyse chlorophyll and carotenoid pigments in cyanobacteria and algae from the Baltic Sea, belonging to different taxonomic groups. The following species were used: Cyclotella meneghiniana - diatom, Oocystis submarina - green alga and Phormidium amphibium - cyanobacterium. Investigations on a favourable method of chlorophyll and carotenoid pigment separation have been carried out. This method allowed to separate the following pigments: lutein and zeaxanthin; diadinoxanthin and fucoxanthin; chlorophyll c1 and c2, into sharp peaks. It could be presumed that the method would be useful and universal in the identification of pigments in other algal and cyanobacteria species and natural phytoplankton assemblages.

5

Wykorzystanie HPLC do oznaczania witamin rozpuszczalnych w tłuszczach

75%

Wieliński S. , Olszanowski A.

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tom [Z] 55, 11-12

1075-1102

EN

In this review, selected chemical techniques such as TLC, UV-VIS, GC, HPLC and microbiological procedures (published since 1960) used for simultaneous determination of fat-soluble vitamins in different matrices have been discussed. Particular attention has been given to HPLC methods, not only in terms of chromatographic conditions, but also in comparison with other separation techniques. HPLC methods have been shown to have clear advantages over existing chemical or microbiological assays in terms of sensitivity, specificity and sample throughput for the analysis of these vitamins. In order to assist the analyst in the selection of a particular procedure, certain chromatographic conditions have been listed for this purpose. However, as currently, no specific HPLC procedures can be recommended, it was decided to develop new methods for these vitamins. Within the past 30 years, HPLC has become the predominant method for separation and quantification of fat-soluble vitamins. The two major, distinct methods of HPLC separation are referred to as normal-phase chromatography and reverse-phase chromatography. To generalise, reverse-phase HPLC is frequently preferred for analysis of biological samples as the columns are more easily purged of any contaminants and sample separation is usually less sensitive to slight changes in mobile-phase composition. A summary of HPLC systems used for fat-soluble vitamins analysis is provided in Table 1 [60-106] and 2 [107-152] in format: compounds determined, matrix, sample preparation and clean up, column, mobile phase, detection, time of analysis, reference. Finally, this paper describes a procedure for the simultaneous determination of vitamin A (retinol acetate, palmitate), vitamin D3 (cholecalciferol), vitamin E (alpha-tocopherol acetate) and alphacalcidol in capsules from a single sample extract using reverse phase HPLC and column backflushing techniques [162-165]. The procedure eliminates saponification, lengthy extractions and sample workup. It is specific to the compounds of interest, shows very good internal precision and is free of interference compared to current published methods.

6

Walidacja metody HPLC stosowanej dla kontroli procesu mycia aparatury przy wytwarzaniu substancji farmaceutycznej

63%

Baran P. A. , Bielejewska A. , Glice M. M. , Beczkowicz H. , Maruszak W. , Kosmacińska B. , Gołębiewski P.

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tom T. 86, nr 8

747-750

7

Wykorzystanie nowoczesnych metod w badaniach niezawodnościowych amunicji eksploatowanej w SZ RP

63%

Kamieńska-Duda A. , Prasuła P.

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tom R. 44, z. 135

91--101

PL

W artykule przedstawiono wybrane przypadki zastosowania nowoczesnych metod analizy fizykochemicznej (metodę chromatograficzną HPLC oraz termiczną DSC) w badaniach amunicji, w sytuacjach wymagających uzyskania danych identyfikacyjnych substancji nieznanego pochodzenia w krótkim czasie. Artykuł jest kontynuacją badań realizowanych w Zakładzie Badań Materiałów Wybuchowych przedstawionych w pracy „Szczególne przypadki wad materiałów wybuchowych”.

EN

The paper presents selected cases of using modern physicochemical analysis methods (HPLC chromatography and thermal DSC methods) for testing ammunition when the identification data of material with unknown origin is required in a short period of time. The following paper is a continuation of the work conducted in Research and Testing Department of High Explosives presented in publication “Particular cases of explosive material defects”.

8

Validation of the assay and purity determination of the FOX-7 (1,1-diamino-2,2-dinitroethylene) using HPLC method

51%

Kamieńska-Duda A. , Kasprzak P.

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tom R. 43, z. 130

79--87

EN

1,1-diamino-2,2 dinitroethylen (DADNE, FOX-7) is a novel explosive with low sensivity. The valuable properties is a result of specific chemical construction, in which inter- and intramolecular hydrogen bonds stabilize the structure. From the reason of low sensivity, FOX-7 has a very broad spectrum of use for elaborating many kinds of munnition. Hence a very important aspect is to conduct the research of this substance to determine chemical purity, assay content of water etc. The HPLC method is the one of the analytical technique which has a very high precision of determination of the purity and assay of the substance. The aim of this work was to compile a new method of the assay and purity determination of FOX-7. The C18-Xbridge column and the mobile phase: Acetonitryle: Water: Triethylamine were used. Through application of the C18- XBridge column and mobile phase the substrate MPD and main substance FOX-7 had very good resolution and the analysis time was relatively short. The validation of the new method has been performed: selectivity, specificity, linearity, precision, assay and limits of detection and quantitation. We have also checked the stress tests of the FOX-7 in acidic, basic and oxidative conditions.

PL

1,1-diamino-2,2 dinitroetylen (DADNE, FOX-7) jest nowoczesną małowrażliwą substancją wybuchową. Jej cenne właściwości są rezultatem specyficznej budowy chemicznej, w której wewnątrz i zewnątrz cząsteczkowe wiązania wodorowe stabilizują strukturę, powodując jej małą wrażliwość na bodźce. Dzięki takim właściwościom, FOX-7 może być zastosowany do elaboracji wielu rodzajów małowrażliwej amunicji. Dlatego tak ważnym aspektem jest prowadzenie badań chemicznych uwzględniających czystość i zawartość chemiczną tej substancji. Metoda HPLC jest nowoczesną techniką, szeroko stosowaną do określenia tych parametrów z dużą dokładnością i precyzją. Celem naszej pracy było zwalidowanie nowej metody oznaczania czystości i zawartości FOX-7. Do oznaczania tych parametrów użyto kolumny C-18 X-Bridge natomiast jako fazy ruchomej mieszaniny acetonitrylu trietyloaminy: wody zmieszanej w odpowiednim stosunku. Zastosowanie właśnie takiej kolumny oraz fazy z modyfikatorem pozwoliło na podzielenie zanieczyszczenia MPD od substancji głównej w odpowiednio krótkim czasie z dobrą rozdzielczością oraz symetrią pików. Walidacja metody obejmowała: selektywność, specyficzność, precyzję, dokładność oraz limity detekcji oraz oznaczalności. Podczas walidacji zostały również przeprowadzone testy stresowe w warunkach kwaśnych, zasadowych oraz utleniających.