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A rapid and sensitive method has been developed for the simultaneous determination of ephedrine and N-methylephedrine in urine samples by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI MS/MS). The samples were extracted with Oasis MCX solid phase extraction cartridges and measured in the modes of electrospray positive ionization (ESI +) and multiple reaction monitoring (MRM). Good linearities were observed in the range of 0.025 0 - 2.50 microg/L with correlation coefficient over 0.999 0 for both analytes. The recoveries were above 80% with RSDs less than 5.0%. The limits of detection were 0.01 microg/L. The method proves to be rapid and sensitive for the trace determination of ephedrine and N-methylephedrine in urine samples.

A rapid, specific and sensitive ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of four trace alkaloids, including aconitine (AC), hypaconitine (HA), mesaconitine (MA) and yunaconitine (YA) in human urine samples. UPLC-MS-MS system coupled with an electrospray ionization (ESI) source was performed in multiple reaction monitoring (MRM) mode. The sample preparation was performed with hollow fiber microextraction (HF-LPME) prior to the analysis. The enrichment factors of the four alkaloids were 102 - 301. The separation was applied on a Waters ACQUITY UPLC BEH C18 column (50 mm x 2.1 mm, 1.7 micro m) with a gradient elution of acetonitrile and 10 mmol/L NH4HCO3, as mobile phase. The retention times , were less than 3 min. This method significantly improved the detection sensitivity, and the limits of quantitation were from 0. 01 to 0.1 ng/L. The calibration curves were linear over the ranges of 0.01 - 10 ng/L for AC, MA and YA, 0.1 - 100 ng/L for HA in human urine samples, and the correlation coefficients were 0. 998 1, 0.998 4, 0.999 5 and 0.998 6, respectively. The method was proved to be rapid and sensitive for aconitum alkaloid analysis in urine samples.

A simple hollow fiber based centrifuge ultrafiltration pretreatment procedure has been developed for the analysis of active components with high polarity in Chinese traditional and herbal drugs which usually contain macromolecule impurities. The procedure combined with HPLC was applied to the determination of hesperidin in Huoxiangzhengqi water. Sample solutions were purified by our patent hollow fiber centrifuge ultrafiltration device. Under the effect of the centrifgual force, micromolecules were removed from solution samples, thus it increased the service life of the column. The accuracy and repeatability of this method have also been improved. The separation was carried out on a Promosil C18 column (4.6 mm x 150 mm, 5 microm) with methanol -0.5% acetic acid solution (35:65) as mobile phase at a flow rate of 1.0 mL x min(-1). The detector wavelength was 283 nm and the column temperature was 30 degrees C. A good linear relation was obtained in the range of 4.69 - 150 mg x L(-1) (r = 0.999 7) and the average recovery was 103.0% with RSD of 1.9%. This method is simple, rapid and accurate, and it provides a simple and cheap ultrafiltration means for the analysis of the polar components in Chinese traditional and herbal drugs.