Extraction of Channel Catfish Muscle Oil by Supercritical Carbon Dioxide and Determination of Fatty Acids by Gas Chromatography- Electron Ionization-Mass Spectrometry / 分析化学

A novel method was established for the qualitative and quantitative determination of fatty acids in Channel Catfish muscle by gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) after supercritical carbon dioxide fluid extraction (SFE-CO_2). The extraction parameters for the methodology were optimized). The optimal conditions were extraction pressure of 25 MPa at 45 ℃ and extraction time of 100 min at the rate of carbon dioxide 30 L/h. The fatty acids in the muscle oil were derived by boron-trifluoride method). The saponification time was 10 min, and the esterication time was 20 min. The obtained fatty acid methylesters were separated by gas chromatography using a HP-Innowax capillary column, and were detected by electron) ionization) mass spectrometry. Full scan mode and SIM mode were used for the qualitative and quantitative analysis), respectively. In the SIM mode, saturated fatty acids were determined with m/z 74, mono-unsaturated) fatty acids were determined with m/z 55, double-unsaturated fatty acids were determined with m/z 67, and polyunsaturated fatty acids were determined with m/z 79. The detection limits of 14 fatty acids were 2.2-20.0 μg/L(S/N=3)), and the quantitative limits were 7.39-59.85 μg/L(S/N=10). The recoveries fell in the range from 90.0% to 111.2%(n=4), and the relative standard deviation was between) 2.0% and 5.9%. This effective, sensitive and reproducible method can be used for the determination of fatty acids in Channel Catfish muscle sample.

Extraction of polysaccharide from Poacynum Hoacynum leaves and component analysis / 中成药

AIM: To extract and isolate polysaccharide from Poacynum Hendersonii leaves,determine its content and analyze the monosaccharide composition.METHODS: Poacynum Hendersonii leaves was extracted with hot water,crude polysaccharide was precipitated with ethanol,deproteinated according to Sevage method,coloured with acticarbon.Then of polysaccharide contents were measured by anthrone-H_2SO_4 colorimetry at the wavelength of 620 nm.The monosaccharide composition was determined by HPCE.RESULTS: The polysaccharide content was 0.97% of leaf weight,and Gal,Ara,and Man contents were three higher monosaccharides.CONCLUSION : The method is easy to carry out the baseline resolution in HPCE and has highly sensitivity.