Determination of Scutellarin in Rabbit Plasma after Oral Administration by HPLC-MS with Solid-Phase Extraction

Aim To establish a sensitive and specific liquid chromatography-massspeetrometry method for determination of scutellarin in rabbit plasma after oral administration.Methods For the quantitative analysis, rutin was used as an internal standard and solid-phaseextraction (SPE) was performed by using a Phenomenex C_8 cartridge. HPLC was carried out using aZorbax Extend-C_(18) column (150 mm x 2.1 mm ID, 5 μm) with a guard cartridge (Phenomenex) .Gradient elution was selected with the mobile phase of methanol 10 mmol·L^(-1) ammonium acetatesolution (pH adjusted to 8.0 with ammonia solution). The flow rate of mobile phase was 0.4mL·min^(-1) and the column temperature was 35 ℃ . Both scutellarin and the internal standard rutinin rabbit plasma extracts were detected by mass spectrometry using an ESI interface in the negativeion mode. Results The linear range was from 2 to 200 ng· mL^(-1), with acceptable accuracy andprecision (RSD) . Conclusion A sensitive, reliable and accurate method for the quantitation ofscutellarin in rabbit plasma has been established.

Behavior of different phosphorus species in suspended particulate matter in the Changjiang estuary

Suspended particulate matter （SPM） collected in the Changjiang （Yangtze River） estuary in June 2006 was separated into five fractions via water elutriation： clay-very fme silt （〈8 μm）, fine silt （8-16 μm）, medium silt （16--32 μm）, coarse silt （32~53 μm） and sand （〉63 μm）. The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction method to obtain six species of phosphorus： exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth to the gate of the fiver mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount of exchangeable P appeared around the gate of the fiver mouth. From the gate of the river mouth to the sea, exchangeable P and organic P in suspended panicles increased distinctly. The total particulate P flux into the estuary from the Changjiang River was about 45.45×10^8μmol/s during sampling. Of this, about 8.27×10^8μmol/s was associated with the ＂truly suspended＂ fraction. The bio-available particulate P flux was about 13.58×10^8μmol/s. Of this, about 4.24 ×10^8μmol/s w as transported by ＂truly suspended＂ particles.

An efficient approach of EEG feature extraction and classification for brain computer interface

In the study of brain-computer interfaces,a method of feature extraction and classification used fortwo kinds of imaginations is proposed.It considers Euclidean distance between mean traces recorded fromthe channels with two kinds of imaginations as a feature,and determines imagination classes using thresh-old value.It analyzed the background of experiment and theoretical foundation referring to the data sets ofBCI 2003,and compared the classification precision with the best result of the competition.The resultshows that the method has a high precision and is advantageous for being applied to practical systems.