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Due to a pH-sensitive effect in many fish hemoglobins (Hb), analytical errors may occur when mammalian Hb is used as a standard in quantitative spectrophotometric multicomponent analysis of fish blood. The aim of this work was to examine differences in the optical spectra of mammalian (human) and fish (farmed Atlantic cod) Hb subjected to pH 7.4 and 6.5. The absorption spectra of the common derivatives, deoxy- (HHb), oxy- (OHb), carboxy- (COHb), and methemoglobin (metHb), were determined in the spectral range of 450-700 nm. The metHb spectra of fish differed considerably from the corresponding human Hb spectra, whereas only minor differences in OHb, HHb, and COHb were found. Cod Hb was significantly (P < 0.05) influenced by a drop in pH compared to mammalian Hb. This resulted in deoxygenation of the Hb and increased autoxidation. For human Hb, a pH-independent isosbestic point in the spectra of OHb, HHb, and metHb at 523 nm was found. This isosbestic point was not found in the absorption spectra of cod Hb. In conclusion, spectra of cod metHb and human metHb behave differently. This must thus be taken into account in spectrophotometric multicomponent analysis. Ideally, Hb in muscle or blood should be determined by comparison to a standard made from the same species. 相似文献
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A thin film of well-ordered anatase TiO2 nanotubes prepared by anodic oxidation of titanium metal were synthesised and used as adsorbent medium for the purification of water from aqueous uranium and lead. The amount of subtracted metal ions was quantified by using X-ray photoelectron spectroscopy at the surface of the reacted TiO2 surface. Batch experiments for the sorption of U and Pb at the surface of the titania substrate were carried out in separated solution equilibrated with air of uranyl acetate and lead nitrate, in the pH range 3?C9. For uranium, the experiments were also repeated in anoxic (N2) atmosphere. The amount of metal ions adsorbed onto the titania medium was quantified by measurements of the surface coverage expressed in atomic percent, by recording high-resolution XPS spectra in the Ti2p, U4f and Pb4f photoelectron regions. Adsorption of the uranyl species in air atmosphere as a function of pH showed an adsorption edge near pH 4 with a maximum at pH 7. At higher pH the presence of very stable uranyl?Ccarbonate complexes prevented any further adsorption. Further adsorption increased until pH 8.5 was obtained when the uranyl solution was purged from dissolved CO2. Lead ion showed a sorption edge at pH 6, with a maximum uptake at pH 8. The results showed that the uptake of uranium and lead on the selected titania medium is remarkably sensitive to the solution pH. This study demonstrates the reliability of this type of material for treating water polluted with heavy metals as well as leachates from radioactive nuclear wastes. 相似文献
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Sophie Jensen Oddny Ragnarsdottir Ragnar Johannsson 《Journal Of Aquatic Food Product Technology》2019,28(1):74-83
The furan fatty acid (F-fatty acid) content was determined in different marine sources as well as in commercially available marine oil products that claim to be health promoting. The five F-fatty acids typically representing the majority of F-fatty acids in fish, 9M5 (9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid), 9D5 (9-(3-dimethyl-5-pentylfuran-2-yl)-nonanoic acid), 11D3 (11-(3,4-Dimethyl-5-propylfuran-2-yl)-undecanoic acid), 11D5 (11-(3,4-Dimethyl-5-pentylfuran-2-yl)-undecanoic acid), and 11M5 (11-(3-Methyl-5-pentylfuran-2-yl)-undecanoic acid) were measured as methyl esters using a gas chromatograph linked with a tandem mass spectrometer (GC/MS-MS). The results showed a significant difference in F-fatty acid levels between the different marine oil products analyzed, depending on the source of raw material. Of the 11 different Icelandic marine catches analyzed, the highest total amount of F-fatty acids was found in the farmed fish. 相似文献
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