mass spectral fragmentation pattern
Recently Published Documents


TOTAL DOCUMENTS

52
(FIVE YEARS 0)

H-INDEX

7
(FIVE YEARS 0)

2016 ◽  
Vol 6 (1) ◽  
pp. 46-49
Author(s):  
Mohd Alhafiizh Zailani ◽  
Fasihuddin Badruddin Ahmad

The oil from stems, leaves and roots of Elephantopus scaber Linn. were extracted by solvent macerationtechnique. The percentage yield oil from stems, leaves and roots are 0.001%, 0.003% and 0.04%, respectively.The stem oil gives major constituents of pentacosane (12.3%), lupenyl acetate (11.7%) and fern-7-en-3β-ol(11.0%), while the leaf oil contains isooctyl phthalate (19.2%), hexadecanoic acid (15.0%) and α-linolenic acid(5.0%) as the major components. The major constituents identified in the root oil are hemellitol (11.6%), octylphthalate (6.0%), 1-nonadecanol (5.6%) and 1-octadecanol (5.5%). There were only three compounds detectedand identified in all three parts of the plant, namely decanedioic acid, bis-(2-ethylhexyl)ester, dotriacontane andpentacosane. The oils were analysed by gas chromatography-mass spectrometer and the compounds wereidentified by comparison with the mass spectral fragmentation pattern database.


2002 ◽  
Vol 14 (4) ◽  
pp. 295-302 ◽  
Author(s):  
Irina Rudik ◽  
Margie R. Cummings ◽  
Robert H. Poppenga

A simple, rapid, and sensitive method for isolation and detection of macrolide endectocides (moxidectin, doramectin, selamectin, ivermectin, and eprinomectin) in animal sera and liver is described. Fortified sera or homogenized liver samples were treated with sodium chloride followed by organic solvent extraction. No additional steps were required prior to analysis. Separation of analytes and collection of mass information was achieved by liquid chromatography/mass spectrometry with positive atmospheric pressure chemical ionization set in selected ion monitoring mode with each sample analysis complete in 15 minutes. Presence of each compound was confirmed based on 2 separate extracted ion profiles. Detection of avermectins and moxidectin in a range of working standards was achieved at 10, 50, and 100 ppb. Quantitation of these compounds in fortified samples was based on standard calibration curves with R2 > 0.99. Detection limits of 10 ppb for ivermectin, moxidectin, and doramectin, 50 ppb for selamectin, and 100 ppb for eprinomectin were achieved in spiked sera. Recoveries of avermectins and moxidectin in 500 ppb fortified sera fell between 61 and 89% (±5.7–15.7). Analysis of fortified liver gave comparable results with recovery of selamectin of 83–91% ± 18.3. A complete mass spectral fragmentation pattern of selamectin and affordable screening method for 6 macrolide endectocides are reported. Method comparison for salt treatment and solid-phase extraction of fortified samples is discussed.


1989 ◽  
Vol 44 (6) ◽  
pp. 690-698 ◽  
Author(s):  
Roland Vogt ◽  
Reinhard Schmutzler

Reaction of N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea (1) with dichlorophosphines. RPCl2 (R = Et: 14; R = Pr: 15) has furnished the P-chloro-substituted acyclic diphosphorus compounds, 16 and 17. In the analogous reaction of 1 with Ph2PCl the corresponding bis(diphenylphosphino)-substituted derivative, 21 was formed. Dehalogenation of 11, 16 and 17 with oxalic acid bis(trimethylsilyl) ester, 22 has produced the mixed-valent cyclic λ3P,λ4P-diphosphorus compounds, 23-25 in almost quantitative yield. Oxidation of the λ3P atom in 23-25 with tetrachloroorthobenzoquinone, 26 has given rise to partial cleavage of the P-P bond, and only moderate yields of the products, 29, 31 and 32, have been obtained. The characterization of the various compounds obtained rests, especially, on their 1H and 31P NMR spectra, and on a study of their mass spectral fragmentation pattern


Sign in / Sign up

Export Citation Format

Share Document