|
|
Analysis of the preferred conformations and determination of the concentrations of ephedrine and pseudoephedrine based on hollow fiber liquid-phase microextraction
CHEN Xuan, BAI Xiaohong*, WANG Xiao, WANG Jing, BU Wei
2010, 28 (12):
1144-1149.
DOI: 10.3724/SP.J.1123.2010.01144
The preferred conformations of the ephedrine and pseudoephedrine in Ephedra sinica Stapf and rat urine were analyzed by the hollow fiber liquid-phase microextraction (HF-LPME) and their extraction mechanisms were illuminated. The method of the separation of the ephedrine and pseudoephedrine and the determination of their concentrations with high performance liquid chromatography (HPLC) were established. The optimal experimental conditions were as follows: the organic phase carrier was the hollow fiber of polyvinylidene fluoride (MOF-503), organic solvent was n-hexanol, the extraction time was 35 min, the stirring rate was 1200 r/min, the sample phase was the NaOH solution (5 mol/L) of the analyte, the acceptor was 0.01 mol/L H2SO4 solution. The extracts were analyzed by HPLC. Under the optimal conditions, the method is convenient and highly sensitive. In Ephedra sinica Stapf, the linear ranges of ephedrine and pseudoephedrine were 5~100 μg/L, the detection limits were 1.9 μg/L and 1.2 μg/L and the enrichment factors were 38 and 61, respectively. The average recoveries of ephedrine and pseudoephedrine were 100.6%±1.2% and 103.2%±3.5%, respectively. In rat urine, their linear ranges were 100~5×104 μg/L, the detection limits were 30 μg/L and 42 μg/L and the enrichment factors were 20 and 17, respectively. In rat urine, their average recoveries were 108.4%±4.4% and 106.1%±5.4%, respectively. The obtained results indicated that the method can be successfully applied for the extraction and determination of the ephedrine and pseudoephedrine in Ephedra sinica Stapf and rat urine.
|
