title: Sensitive and direct determination of lithium by mixed-mode chromatography and charged aerosol detection.
abstract: A sensitive analytical method using mixed mode HPLC separation coupled with charged aerosol detection (CAD) was developed for quantitative analysis of lithium. The method is capable of separating lithium ion from different drug matrices and other ions in a single run thus eliminating the organic matrix and ionic analyte interferences without extensive sample preparation such as derivatization and extraction. The separation space and chromatographic conditions are defined by systematic studies of the retention behaviors of lithium and potential interfering ions and different type of pharmaceutical APIs (active pharmaceutical ingredients) under reversed-phase, HILIC and cation/anion exchange mechanisms. Compared to other current analytical techniques for lithium analysis, the presented method provides a new approach and demonstrates high sensitivity (0.02ng for LOD and 0.08ng for LOQ in both standard and sample solution). The method has been validated for pharmaceutical samples and can be potentially applied to biological, food and environmental samples.
authors.affiliation: Genentech Inc, Small Molecule Pharmaceutical Science, 1 DNA Way, South San Francisco, CA 94080, USA.
authors.forename: Lulu
authors.initials: L
authors.lastname: Dai
authors.affiliation: Genentech Inc, Small Molecule Pharmaceutical Science, 1 DNA Way, South San Francisco, CA 94080, USA.
authors.forename: Larry
authors.initials: L
authors.lastname: Wigman
authors.affiliation: Genentech Inc, Small Molecule Pharmaceutical Science, 1 DNA Way, South San Francisco, CA 94080, USA. Electronic address: zhang.kelly@gene.com.
authors.forename: Kelly
authors.initials: K
authors.lastname: Zhang
mesh_terms: D000336:Aerosols; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D056148:Chromatography, Reverse-Phase; D006863:Hydrogen-Ion Concentration; D018020:Lithium Compounds / Q000032:analysis*; D009994:Osmolar Concentration; D012680:Sensitivity and Specificity
chemical_list: D000336:Aerosols; D018020:Lithium Compounds
keywords: CAD detection; Lithium; Mixed-mode chromatography; Pharmaceutics; Trace analysis