title: NACE-ESI-MS combined with on-line concentration for high-sensitivity analysis of quinolizidine alkaloids.
abstract: A rapid, reproducible and high-sensitivity NACE-ESI-MS method was developed for the analysis of sophoridine, matrine, sophocarpine and oxymatrine in the roots of Sophora flavescens Ait. and S. tonkinensis Gagnep. Field-amplified sample stacking with electromigration-injection (FASS-EMI) was first used in NACE for the on-line concentration of the alkaloids. The conditions of NACE separation, FASS-EMI stacking and MS detection were systematically optimized. The optimum NACE buffer was an electrolyte containing 50 mM ammonium acetate, 0.5% acetic acid and 30% ACN in methanol. The sensitivity was improved by about 100-fold by the FASS-EMI technique, which was further improved by more than 1000-fold with MS detection. The RSDs (n = 6) of the relative migration time and relative peak area of each peak were less than 0.3 and 2.4% for intra-day and less than 5.1 and 6.0% for inter-day, respectively. The LODs (S/N = 3) of analytes were determined to be 0.0210-0.0446 ng/mL. A bioanalytical method based on this NACE-ESI-MS method may be developed for the analysis of the alkaloids in biological sample matrices (plasma, urine, etc.) after effective ion removal.
authors.affiliation: Pharmaceutical Informatics Institute, Zhejiang University, Hangzhou, P. R. China.
authors.forename: Shufang
authors.initials: S
authors.lastname: Wang
authors.forename: Haibin
authors.initials: H
authors.lastname: Qu
authors.forename: Yiyu
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D000470:Alkaloids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D000432:Methanol; D015394:Molecular Structure; D011807:Quinolizines / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry*; D029909:Sophora / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D000470:Alkaloids; D011807:Quinolizines; D012997:Solvents; D000432:Methanol