Home  About us  Contact
 

Ionization-tandem Mass Spectrometry (ionization-tandem + mass_spectrometry)

Distribution by Scientific Domains
Chemistry75%

Selected Abstracts

Analysis of sesquiterpene lactones in Eupatorium lindleyanum by HPLC-PDA-ESI-MS/MS

PHYTOCHEMICAL ANALYSIS, Issue 2 2010
Nian Yun Yang
Abstract Introduction , The aerial part Eupatorium lindleyanum is commonly used as an antipyretic and detoxicant clinically in traditional Chinese medicine. Our previous research showed that germacrane sesquiterpene lactones were its main active constituents, so the development of rapid and accurate methods for the identification of the sesquiterpene lactones is of great significance. Objective , To develop an HPLC-PDA-ESI-MS/MS method capable for simple and rapid analysis of germacrane sesquiterpene lactones in the aerial part E. lindleyanum. Methodology , High-performance liquid chromatography-photodiode array detection-electrospray ionization-tandem mass spectrometry was used to analyze germacrane sesquiterpene lactones of Eupatorium lindleyanum. The fragmentation behavior of germacrane sesquiterpene lactones in a Micromass Q/TOF Mass Spectrometer was discussed, and 9 germacrane sesquiterpene lactones were identified by comparison of their characteristic data of HPLC and MS analyses with those obtained from reference compounds. Results , The investigated germacrane sesquiterpene lactones were identified as eupalinolides C (1), 3,-acetoxy-8,-(4,-hydroxy-tigloyloxy)-14-hydroxy-costunolide (2), eupalinolides A (3), eupalinolides B (4), eupalinolides E (5), 3,-acetoxy-8,-(4,-oxo-tigloyloxy)-14-hydroxy-heliangolide (6), 3,-acetoxy-8,-(4,-oxo- tigloyloxy)-14-hydroxy-costunolide (7), hiyodorilactone B (8), and 3,-acetoxy-8,-(4,-hydroxy-tigloyloxy)- costunolide (9). Compounds 6, 7 and 9 were reported for the first time. Conclusion , HPLC-PDA-ESI-MS/MS provides a new powerful approach to identify germacrane sesquiterpene lactones in E. lindleyanum rapidly and accurately. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Survey of albumin purification methods for the analysis of albumin-organic toxicant adducts by liquid chromatography-electrospray ionization-tandem mass spectrometry

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2005
Carrie L. Young
Abstract HSA has been shown to react with many organic toxicants to form adducts that are useful biomarkers for exposure. Albumin isolation is an important first step for the analysis of these protein-toxicant adducts. We tested several approaches to isolate albumin from serum treated with an electrophilic organic toxicant known to form adducts with albumin, i.e., sulfur mustard agent (HD) (2,2'-dichloroethyl sulfide), in order to evaluate these techniques as purification methods. To select the most efficient isolation strategy, methods were evaluated using gel electrophoresis, total protein quantitation, and peptide-adduct identification by MS. Results suggest that the albumin-rich fractions obtained can be used to identify exposure by quantitating the albumin adducts to electrophilic organic toxicants such as HD. The HiTrap Blue HP albumin isolation system appears to display the most promising results for purifying albumin to detect HD-adducts, exhibiting high purification efficiency, satisfactory albumin recovery, promising specificity, and a higher loading capacity for serum. [source]

The In Vivo Response of Novel Buprenorphine Metabolites, M1 and M3, to Antiretroviral Inducers and Inhibitors of Buprenorphine Metabolism

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 3 2009
David E. Moody
The identification of two, M1 and M3, in urine suggests that they may be quantitatively significant metabolites. To further understand the in vivo regulation of this mode of metabolism, we evaluated 24-hr urine from subjects (10 per treatment group) on buprenorphine alone or with the antiretroviral agents: efavirenz, delavirdine, nelfinavir, ritonavir, and lopinavir/ritonavir. Quantitative analysis for buprenorphine and traditional metabolites and semi-quantitative analysis of M1 and M3 in urine were performed by liquid chromatography-electrospray ionization-tandem mass spectrometry. The renal clearance of buprenorphine and traditional metabolites were similar for all treatments except for lopinavir/ritonavir, suggesting that urine amounts of M1 and M3 would adequately reflect systemic changes (except lopinavir/ritonavir). Efavirenz decreased M1 and increased M3 consistent with its ability to induce cytochrome P450 (CYP) 3A. Delavirdine increased M1 and decreased M3 consistent with its ability to inhibit CYP3A. Both nelfinavir and ritonavir decreased both M1 and M3, consistent with their ability to inhibit CYP3A and 2C8. These results provide further information on the in vivo response of novel secondary metabolites of buprenorphine to metabolic inhibitors and inducers. [source]

Synthesis of benzofurazan derivatization reagents for short chain carboxylic acids in liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS)

BIOMEDICAL CHROMATOGRAPHY, Issue 4 2009
Tomofumi Santa
Abstract Benzofurazan derivatization reagents, 4-[2-(N,N -dimethylamino)ethylaminosulfonyl]-7-(2-aminopentylamino)-2,1,3-benzoxadiazole (DAABD-AP) and 4-[2-(N,N -dimethylamino) ethylaminosulfonyl]-7-(2-aminobutylamino)-2,1,3-benzoxadiazole (DAABD-AB), for short-chain carboxylic acids in liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) were synthesized. These reagents reacted with short chain carboxylic acids in the presence of the condensation reagents at 60°C for 60 min. The generated derivatives were separated on the reversed-phase column and detected by ESI-MS/MS with the detection limits of 0.1,0.12 pmol on column. Upon collision-induced dissociation, a single and intense product ion at m/z 151 was observed. These results indicated that DAABD-AP and DAABD-AB are suitable as the derivatization reagents in LC/ESI-MS/MS analysis. Copyright © 2008 John Wiley & Sons, Ltd. [source]