| 1. |
- Isaac, Giorgis, et al.
(författare)
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Total Lipid Extraction of Homogenized and Intact Lean Fish Muscles Using Pressurized Fluid Extraction and Batch Extraction Technique
- 2005
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 53:14, s. 5506-5512
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Tidskriftsartikel (refereegranskat)abstract
- The reliability and efficiency of pressurized fluid extraction (PFE) technique for the extraction of total lipid content from cod and the effect of sample treatment on the extraction efficiency have been evaluated. The results were compared with two liquid-liquid extraction methods, traditional and modified methods according to Jensen. Optimum conditions were found to be with 2-propanol/n-hexane (65:35, v/v) as a first and n-hexane/diethyl ether (90:10, v/v) as a second solvent, 115 oC, and 10 min of static time. PFE extracts were cleaned up using the same procedure as in the methods according to Jensen. When total lipid yields obtained from homogenized cod muscle using PFE were compared yields obtained with original and modified Jensen methods, PFE gave significantly higher yields, ~10% higher (t test, P < 0.05). Infrared and NMR spectroscopy suggested that the additional material that inflates the gravimetric results is rather homogeneus and is primarily consists of phospholipid with headgroups of inositidic and/or glycosidic nature. The comparative study demonstrated that PFE is an alternative suitable technique to extract total lipid content from homogenized cod (lean fish) and herring (fat fish) muscle showing a precision comparable to that obtained with the traditional and modified Jensen methods. Despite the necessary cleanup step, PFE showed important advantages in the solvent consumption was cut by ~50% and automated extraction was possible.
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| 2. |
- Persson, Linn, et al.
(författare)
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Electrospray mass spectrometry to study lake water DOM and effects of microbial degradation
- 2005
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Ingår i: International Journal of Environmental Analytical Chemistry. - : Taylor & Francis Group. - 0306-7319 .- 1029-0397. ; 85:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- Qualitative analysis of lake water dissolved organic matter (DOM) was carried out using electrospray ionization mass spectrometry (ESI MS) without prior clean-up or chromatography, showing the potential of ESI MS as a rapid method to analyse qualitative differences between DOM with different environmental properties. Spectra were evaluated in terms of the relative ion abundance in certain mass to charge ranges (m/z(range)), and the mass-to-charge average (m/z(average)). Lake water DOM from two different sources was used. In addition, DOM from both sources that had been subjected to microbial degradation under different oxygen regimes was analysed. ESI MS results were compared with those of UV absorbance and pollutant binding capacity (pyrene and atrazine). The results from all methods indicated qualitative differences between the DOM from different lakes, but only minor qualitative changes when comparing oxic and anoxic degradation. To detect those small differences the m/z(range) proved to be the more sensitive evaluation method, compared to the m/z(average).
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