- Synthesis of bisaramil labelled with carbon-14 and deuterium
-
[6,8-14C2]-Bisaramil: 3-methyl-7-ethyl-9α-(4-chlorobenzoyloxy)-3,7-diazabicyclo/3.3.1./nona ne-[6,8-14C2]monohydrochloride and [7-N-D5-ethyl]-Bisaramil: 3-methyl-7-[D5-ethyl]-9α-(4-chlorobe
- Szammer,Simon-Trompler,Mlinko
-
-
Read Online
- Quantification of four major metabolites of embryotoxic N -methyl- and N -ethyl-2-pyrrolidone in human urine by cooled-injection gas chromatography and isotope dilution mass spectrometry
-
N-Methyl- and N-ethyl-2-pyrollidone (NMP and NEP) are frequently used industrial solvents and were shown to be embryotoxic in animal experiments. We developed a sensitive, specific, and robust analytical method based on cooled-injection (CIS) gas chromatography and isotope dilution mass spectrometry to analyze 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N- ethylsuccinimide (2-HESI), two newly identified presumed metabolites of NEP, and their corresponding methyl counterparts (5-HNMP, 2-HMSI) in human urine. The urine was spiked with deuterium-labeled analogues of these metabolites. The analytes were separated from urinary matrix by solid-phase extraction and silylated prior to quantification. Validation of this method was carried out by using both, spiked pooled urine samples and urine samples from 56 individuals of the general population with no known occupational exposure to NMP and NEP. Interday and intraday imprecision was better than 8% for all metabolites, while the limits of detection were between 5 and 20 μg/L depending on the analyte. The high sensitivity of the method enables us to quantify NMP and NEP metabolites at current environmental exposures by human biomonitoring.
- Schindler, Birgit K.,Koslitz, Stephan,Meier, Swetlana,Belov, Vladimir N.,Koch, Holger M.,Weiss, Tobias,Bruening, Thomas,Kaefferlein, Heiko U.
-
-
Read Online
- The Collision-Induced Dissociations of Deprotonated Amines in the Gas Phase
-
The major collision-induced fragmentations of deprotonated primary and secondary amines are best rationalized as proceeding through the intermediacy of ion complexes.For example, the characteristic fragmentation of deprotonated ethylamine is MeCH2NH- -> -(CH2=NH)> -> CH2N- + CH4 Secondary alkylamines behave in a similar fashion.The occurrence of proton transfer as a prelude to fragmentation is rare: the only example observed in this study is the probable reaction PhNEt ->-> PhNHCHMe -> -> -> C7H6N- + CH4 which is preceded or accompanied by proton transfer between the methylene and phenyl substituents.Deprotonated aniline undergoes specific elimination of CNH from the 1-position to form the cyclopentadienyl anion.Finally, retro reactions are observed for the piperazine anion, e.g.HN(CH2CH2)2N- -> -CH2CH2N=CH2 + CH2NH
- Raftery, Mark J.,Bowie, John H.
-
p. 1477 - 1489
(2007/10/02)
-
