Ion-Molecule Reactions of 2-Methoxyethanol with Ketones, Aldehydes, Alcohols and Phenols under Chemical Ionization Conditions

✍ Scribed by Pakarinen, Jaana M. H.; Vainiotalo, Pirjo

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 816 KB
• Volume: 31
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199609)31:9<1003::aid-jms385>3.0.co;2-9

✦ Synopsis

2-Methoxyethanol has been used as a chemical ionization (CI) reagent gas in a conventional ion source and it has been found to produce numerous reagent ions, including an ion at m/z 89, [CH,OCH,CH,OCH,]+. These ions react with different classes of compounds, e.g. by formation of variety of adduct ions. Neutral ketones (RC(0)R')

were observed to yield without exception [ M -R + 441 + and/or [ M -R + 441 + product ions. Similarly, for aldehydes the formation of the product ion [ M -H + 441 + is common. Selectivity was noticed especially for the neutral alcohols studied, which resulted in the formation of [ M + 271 + and [M -t 891 + product ions, and also for the neutral phenols studied, which resulted in the formation of [ M + 131 +, ( M + 271 + and [ M + 891 + product ions. There is a clear correlation between the structure of isomeric neutral alcohols studied and the abundances of the product ion [ M + 89 J + ; the more hindered the alcohol, the lower is the abundance of the [ M + 891 + ion. The [M + 131 + product ion for phenols is a characteristic fragment of the [M + 89]+ ion produced by elimination of neutral 2-methoxyethanol. The greatest abundance of the IM + 131 + ion for m-cresol and the use of labelled compounds and labelled reagent gases, CD,OCH,CH,OH and CH,OCH,CH,OD, suggest that the addition occurs mainly to the aromatic ring, ortho and para positions being more favoured. The collision-induced dissociation technique was used to characterize the structures of the product ions