1,1',3,3'-Tetramethyl-5-(4-methylamino-3-nitrobenzyl)-5,5'-methylenebisbarbituric acid

1976 ◽  
Vol 29 (10) ◽  
pp. 2219 ◽  
Author(s):  
JW Clark-Lewis ◽  
GL Aldous ◽  
MJ Thompson
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Barbituric Acid ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Spectroscopic Methods ◽  
Thermal Fragmentation ◽  
Related Compounds

The previously proposed structure (2) for the compound named in the title is confirmed by spectroscopic methods and by synthesis of related compounds. The barbituric acid undergoes a very facile thermal fragmentation in the mass spectrometer into 1,3-dimethyl-5-(4-ethylamino-3-nitrobenzy1)-barbituric acid (3) (which was also prepared by unambiguous synthesis) and 1,3-dimethyl-5-methylenebarbituric acid (4). The electron-impact, chemical-ionization, and negative-ion mass spectrometric behaviour of the barbituric acid (2) was examined.

Determination of 3,3'-Dichlorobenzidine in Industrial Wastewaters

2004 ◽  
Vol 39 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Hing-Biu Lee ◽  
Thomas E. Peart ◽  
Ken Terry ◽  
James Maguire
Keyword(s):  
Electron Impact ◽  
Chemical Ionization ◽  
Solid Phase ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Ms Detection ◽  
Negative Ion Chemical Ionization ◽  
Ionization Mode ◽  
Wastewater Samples

Abstract A solid-phase extraction, chemical derivatization, and gas chromatography/mass spectrometry (GC/MS) method has been developed for the determination of trace 3,3'-dichlorobenzidine (DCB) in industrial wastewater samples. Instead of an octadecylsilane (ODS) cartridge, a Porapak RDX cartridge was used since the latter could be optimized for the extraction of DCB. After the pre-concentration, interfering coextractives in the sample were selectively removed from the cartridge by elution with a 1:1 mixture of acetonitrile and water. DCB was then eluted with acetonitrile and derivatized with pentafluoropropionic acid anhydride. The product was subsequently analyzed by GC/MS in either the electron impact or negative ion chemical ionization mode. Recoveries of DCB and the surrogate, DCB-d6, were better than 90% at spiking levels of 10, 1, and 0.1 µg/L. Based on a concentration factor of 100, the detection limits for DCB in wastewater samples were determined to be 0.1 µg/L by electron impact GC/MS detection, and 0.01 µg/L by negative ion chemical ionization GC/MS detection, respectively. This method has been successfully applied to wastewater samples collected in the Toronto area.

Comparison of Five Ionization Methods for Producing Mass Spectra of Typical Organophosphorus Pesticides

1978 ◽  
Vol 32 (4) ◽  
pp. 388-399 ◽  
Author(s):  
Kenneth L. Busch ◽  
Maurice M. Bursey ◽  
J. Ronald Hass ◽  
G. Wayne Sovocool
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Organophosphorus Pesticides ◽  
Large Fraction ◽  
Negative Ion ◽  
Oxygen Mixture ◽  
Ion Molecule Reactions ◽  
And Migration ◽  
Positive Chemical Ionization

Positive ion mass spectra obtained by conventional electron impact and by methane chemical ionization were compared with the negative ion mass spectra of 16 typical organophosphorus pesticides using methane, a methane-oxygen mixture, and oxygen as enhancement/reagent gases. In the negative ion spectra, phosphate and phenate anions typically carry a large fraction of the ion current. Displacement of chlorine by oxygen is noted in some cases, and migration of aryl groups from oxygen to sulfur is occasionally noted. Ion-molecule reactions between two species derived from sample molecules have been observed. The sensitivity of the negative ion techniques for the pesticides examined is greater than conventional electron impact or methane positive chemical ionization techniques, and can be up to 800 times more sensitive for some compounds.

scholarly journals Rapid Analysis of PCB in Insulating Oil by Gas Chromatography/Negative Ion Chemical Ionization Mass Spectrometer

2003 ◽  
Vol 13 (4) ◽  
pp. 959-971 ◽  
Author(s):  
Yasuto MACHII ◽  
Osamu KUMAZAKI ◽  
Kenji MIZUNO ◽  
Mitsugu NAGANO ◽  
Yoshio HAYASAKA ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Rapid Analysis ◽  
Negative Ion ◽  
Ionization Mass ◽  
Insulating Oil ◽  
Negative Ion Chemical Ionization
Sign in / Sign up

Export Citation Format

Share Document