Analysis of benzannelated thiophene derivatives by negative-ion chemical ionization using oxygen as a reagent gas

✍ Scribed by G. Drabner; H. Budzikiewicz

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 604 KB
• Volume: 30
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.1190300615

✦ Synopsis

Abstract

Under the conditions of negative‐ion chemical ionization with O~2~ as a reagent gas [NCI(O~2~)], thiophene derivatives suffer surface‐catalysed oxidative degradation with subsequent ionization of the resulting species. These degradation reactions are to some extent structure specific and thus may be used for the localization of rings and/or substituents. It is advisable, however, to combine NCI(O~2~) with either electron impact ionization or positive ion CI. The latter ionization methods yield abundant M^+·^ ions but hardly any structure‐specific fragments, whereas with NCI(O~2~) the determination of the molecular mass may be difficult owing to the competing oxidation reactions.