			Home About us Contact

Chemical Ionization Tandem Mass Spectrometry (chemical + ionization_tandem_mass_spectrometry)

Distribution by Scientific Domains

Chemistry	100%

Kinds of Chemical Ionization Tandem Mass Spectrometry

atmospheric pressure chemical ionization tandem mass spectrometry

pressure chemical ionization tandem mass spectrometry

Selected Abstracts

Ammonia chemical ionization tandem mass spectrometry in structural determination of alkaloids.

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2001

Chemical ionization tandem mass spectrometry (CI-MS/MS) of alkaloids with ammonia reagent gas and collision-activated dissociation as well as EI-MS/MS were applied to the tetraponerine alkaloids in extracts from six pseudomyrmecine ants of the genus Tetraponera. The MS/MS techniques along with gas chromatography Fourier transform infrared (GC/FTIR) spectra allowed identification in two extracts of seven of the eight known tetraponerines. The EI-MS/MS fragmentations proved diagnostic for the ring system and the CI-MS/MS patterns for the C-8 or C-9 substitution, while the Bohlmann bands in FTIR spectra were diagnostic for the C-8 or C-9 configurations. An Indian ant (T. allaborans) had T,2, T,4 and T,8, while a Chinese ant (T. binghami) had T,5, T,6, T,7 and T,8. Four other ants, T. rufonigra (India), T. penzigi (Africa), T. clypeata (Africa) and T. sp. cf. emeryi (Africa), had no tetraponerines. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Structural elucidation of the wheat straw lignin polymer by atmospheric pressure chemical ionization tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2003
Joseph H. Banoub
[source]

Simultaneous characterization of isoflavonoids and astragalosides in two Astragalus species by high-performance liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2007
Xi Zhang
Abstract A method was developed for the simultaneous identification of astragalosides (AGs) and isoflavonoids (IFs) in the roots of Astragalus membranaceus and Astragalus mongholicus by HPLC coupled with atmospheric pressure chemical ionization MS/MS (HPLC-APCI-MS/MS). Diagnostic fragment ions of AGs and different group of IFs were obtained with one AG and eight IF standards analyzed by CID-MS, which were adopted as characteristic MS/MS fingerprints for further identification of these compounds in the two Astragalus species by using HPLC-APCI-MS/MS. A total of 20 IFs and 10 AGs were identified or tentatively identified. Among them, six IFs were detected in A. membranaceus for the first time and five IFs were firstly identified in A. mongholicus. The results indicate that HPLC-APCI-MS/MS is a powerful tool for the simultaneous characterization of IFs and AGs in complex matrix. [source]

Precursor ion scan profiles of acylcarnitines by atmospheric pressure thermal desorption chemical ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2008
Giuseppe Paglia
The fatty acyl esters of L-carnitine (acylcarnitines) are useful biomarkers for the diagnosis of some inborn errors of metabolism analyzed by liquid chromatography/tandem mass spectrometry. In this study the acylcarnitines were analyzed by atmospheric pressure thermal desorption chemical ionization using a commercial tandem mass spectrometer (APTDCI-MS/MS). The method is based on the precursor ion scan mode determination of underivatized acylcarnitines desorbed from samples by a hot desolvation gas flow and ionized by a corona pin discharge. During desorption/ionization step the temperature induces the degradation of acylcarnitines; nevertheless, the common fragment to all acylcarnitines [MH,59]+ is useful for analyzing their profile. APTDCI parameters, including angle of collection and incidence, gas flows and temperatures, were optimized for acylcarnitines. The experiments were performed drying 2,µL of an equimolar mixture of acylcarnitine standards on a glass slide. The specificity was evaluated by comparing product ion spectra and the precursor ion spectra of 85 m/z of acylcarnitines obtained by the APTDCI method and by electrospray ionization flow injection analysis (ESI-FIA). The method was also employed to analyze acylcarnitines extracted from a pathological dried blood spot and a control. The method enables analysis of biological samples and recognition of some acylcarnitines that are diagnostic markers of inherited metabolic diseases. The intrinsic high-throughput analysis of the ambient desorption ionization methods offers a new opportunity either for its potential application in clinical chemistry and for the expanded screening of some inborn errors of metabolism. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Quantitative analyses of indoloquinazoline alkaloids in Fructus Evodiae by high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2006
Yan Zhou
Fructus Evodiae (Wuzhuyu), the fruits of Evodia rutaecarpa and related varieties, is widely used in traditional Chinese medicine. The bioactive constituents include the indoloquinazoline alkaloids rutaecarpine, evodiamine and dehydroevodiamine. A new assay based on high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (HPLC/UV/APCI-MS/MS) was developed for the measurement of the indoloquinazoline alkaloids in commercial Fructus Evodiae products. Initially, the MS/MS fragmentation pathways of indoloquinazoline alkaloids were investigated to identify fragment ions that might be useful for the sensitive and selective detection of trace indoloquinazoline alkaloids during LC/MS/MS. Then, quantitative MS analysis of five indoloquinazoline alkaloids in 12 commercial Fructus Evodiae products from different geographical sources was performed. Analyte recovery was in the range of 97.5,105.3% for all with relative standard deviations (RSDs) below 6%, the intra-assay and inter-assay RSDs were less than 7%, and good linear relationships were shown with correlation coefficients for the analytes exceeding 0.999. Therefore, this LC/MS/MS assay facilitated the rapid quantitative analysis of rutaecarpine, evodiamine, evodiamide, 14-formyldihydrorutaecarpine and dehydroevodiamine in 12 commercial Fructus Evodiae products with excellent recovery, repeatability, accuracy and sensitivity. This method is simple and specific and can be used for identification and quality control of this traditional Chinese remedy. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Analysis of bufadienolides in the Chinese drug ChanSu by high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2005
Min Ye
The qualitative analysis of bufadienolides in the Chinese drug ChanSu was performed using high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS). Bufadienolides are the major bioactive constituents of ChanSu, which is used to treat heart failure and cancer in traditional Chinese medicine. The APCI-MS fragmentation behavior of bufadienolides was studied. For bufadienolides with only hydroxyl substituents, the fragmentation was characterized by successive eliminations of H2O and CO molecules, and the profile of MS/MS product ions was correlated with the number of hydroxyl groups. If a C-16 acetoxyl group was present, the fragmentation of [M+H]+ ions was triggered by initial loss of 60,Da (HOAc). The elimination of CO was significant for bufadienolides with a 19-formyl group, and the 19-hydroxyl group could be characterized by the loss of 30,Da (HCHO). These fragmentation rules were applied to the identification of bufadienolides in a methanolic extract of ChanSu, which was separated on a C18 column with gradient elution. A total of 35 bufadienolides were identified, including four new constituents. The method established here facilitated the convenient and rapid quality control of ChanSu crude drug and its pharmaceutical preparations. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Determination of patterns of biologically relevant aldehydes in exhaled breath condensate of healthy subjects by liquid chromatography/atmospheric chemical ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2003
Roberta Andreoli
A method for the simultaneous determination of several classes of aldehydes in exhaled breath condensate (EBC) was developed using liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI-MS/MS). EBC is a biological matrix obtained by a relatively new, simple and noninvasive technique and provides an indirect assessment of pulmonary status. The measurement of aldehydes in EBC represents a biomarker of the effect of oxidative stress caused by smoke, disease, or strong oxidants like ozone. Malondialdehyde (MDA), acrolein, ,,, -unsaturated hydroxylated aldehydes [namely 4-hydroxyhexenal (4-HHE) and 4-hydroxynonenal (4-HNE)], and saturated aldehydes (n -hexanal, n -heptanal and n -nonanal) were measured in EBC after derivatization with 2,4-dinitrophenylhydrazine (DNPH). Atmospheric pressure chemical ionization of the analytes was obtained in positive-ion mode for MDA, and in negative-ion mode for acrolein, 4-HHE, 4-HNE, and saturated aldehydes. DNPH derivatives were separated on a C18 column using variable proportions of 20,mM aqueous acetic acid and methanol. Linearity was established over 4,5 orders of magnitude and limits of detection were in the 0.3,1.0 nM range. Intra-day and inter-day precision were in the 1.3,9.9% range for all the compounds. MDA, acrolein and n -alkanals were detectable in all EBC samples, whereas the highly reactive 4-HHE and 4-HNE were found in only a few samples. Statistically significant higher concentrations of MDA, acrolein and n -hexanal were found in EBC from smokers. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Mass spectrometric analysis of cyclofenil and its metabolites in human urine

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2002
Seung-Woon Myung
Using gas chromatography/electron impact-mass spectrometry (GC/EI-MS) and high performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry (HPLC/APCI-MS/MS), the structures of cyclofenil metabolites in human urine have been assigned. The hydroxyl metabolites liberated from the glucuronide conjugates after acid hydrolysis were characterized as the trimethylsilyl (O-TMS) derivatives using GC/MS. The conjugate glucuronide forms were detected without hydrolysis by HPLC/MS. Cyclofenil was not observed in urine. Tentative structures for the two metabolites are proposed. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Quantitative determination of perfluorooctanoic acid ammonium salt in human serum by high-performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2002
Cristina Sottani
A sensitive, specific, accurate and reproducible analytical method was developed and validated to quantify perfluorooctanoic acid (PFOA) in human serum. After initial extraction with an ion-paring reagent, the procedure for quantifying PFOA is based on high-performance liquid chromatography (HPLC) interfaced to negative ion tandem mass spectrometry, operating in selected ion monitoring mode. The retention times of PFOA and its internal standard (D,L-malic acid) were 5.85 and 1.70,min, respectively. The assay was linear over the range 0,500,ng/mL, with a lower limit of quantification (LOQ) of 25,ng/mL, and with a coefficient of variation (CV) of 7.3%. The lower limit of detection (LOD) was assessed as 10,ng/mL. The overall precision and accuracy were assessed on three different days. The within- and between-day precision was ,9.7 and 6.8%, respectively, and the accuracy was in the range 96,114%. The mean extracted recovery assessed at three different concentrations (100, 250, and 500,ng/mL) was always more than 85%. With this method no derivatization procedure was needed, thus avoiding possible thermal and chemical decomposition reactions of PFOA. The assay was applied to quantify perfluorooctanoic acid in serum from employees exposed to fluorochemicals commonly used in industrial applications for polymer production. The quantitative results for PFOA blood levels were found to vary between 100 and 982,ng/mL. Copyright © 2002 John Wiley & Sons, Ltd. [source]