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Summary A method was devised to assay four forms of vitamin C: L-ascorbic acid (AA), dehydroascorbic acid (DHA), ascorbate-2-mono-
and polyphosphate (AMP, APP), as well as ascorbate-2-monosulphate (AMS), in sample series of different fish tissues and feed.
Direct and indirect detection were combined. Sample extractions were carried out with 0.2 mol L−1 sodium acetate buffer (pH 4.8) and extracts were deproteinized after different chemical or enzymatic reactions, with perchloric
acid. The DHA was reduced to AA with dithioerythritol (DTE). Ascorbate oxidase enzyme was used for the detection of background
and an acidic phosphatase enzyme for the hydrolysis of different phosphate esters. Ascorbate-2-sulphate was detected directly
with help of coinjection of the compound. Chromatographic analysis was carried out with a single column isocratic reverse
phase method. The mobile phase was an aqueous buffer of 0.04 M sodium-acetate, 0.05 mM EDTA, 0.5 mM tetrabutylammonium dihydrogen
phosphate (TBA) adjusted to pH 3.76 with 85% H3PO4 and with 24 mL methanol added to 1000 mL. C-18 columns were used with 0.6 mL min−1 flow rate at 23°C. The vitamin C forms were detected by UV absorption at 250 nm. The determination limit was 1.0–5.0 μg g−1 in AA equivalent. The standard deviations were between 1–6% and depended on the concentrations of vitamin C forms and tissues.
Recoveries were between 90–96% in samples.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997 相似文献
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Chiara Tognoli Federica Rossi Francesco Di Cola Gabriele Baj Enrico Tongiorgi Genciana Terova Marco Saroglia Giovanni Bernardini Rosalba Gornati 《BMC neuroscience》2010,11(1):4
Background
Stress involves alterations of brain functioning that may precipitate to mood disorders. The neurotrophin Brain Derived Neurotrophic Factor (BDNF) has recently been involved in stress-induced adaptation. BDNF is a key regulator of neuronal plasticity and adaptive processes. Regulation of BDNF is complex and may reflect not only stress-specific mechanisms but also hormonal and emotional responses. For this reason we used, as an animal model of stress, a fish whose brain organization is very similar to that of higher vertebrates, but is generally considered free of emotional reactions. 相似文献
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