title: Studies on 1-alkylamine adduct formation in electrospray ionization mass spectrometry for quantitative analysis.
abstract: We investigated the formation of 1-alkylamine adduct ions using 1,2-, 1,3-, and 1,4-cyclohexanediol (CHD) as model compounds and the relationships of the peak intensity between the protonated molecules ([M+H]+), sodium adduct ions ([M+Na]+), and 1-alkylamine adduct ions ([M+A+H]+) of 16 model compounds using electrospray ionization mass spectrometry. When 1-octylamine was added to 1,2-, 1,3-, and 1,4-CHD solutions, the peak intensity of the 1-octylamine adduct ions ([M+Oct+H]+) was higher than those of [M+H]+ and [M+Na]+. The highest peak intensity of [M+Oct+H]+ was observed in 1,2-CHD, followed by 1,3-CHD and 1,4-CHD and this order was the same as that of [M+Na]+ for CHDs in the solution without 1-octylamine. These results suggest that the mechanism of formation of [M+Oct+H]+ is similar to that of [M+Na]+ and that adduct formation seems to occur between 1-octylamine and two oxygen atoms in CHD in a similar manner to [M+Na]+. Based on these results, 16 model compounds including CHDs were investigated with respect to the relationship between [M+Na]+ and [M+A+H]+. A positive correlation was observed between the peak intensities of [M+Na]+ and [M+A+H]+, supporting that the formation mechanism of [M+A+H]+ is potentially similar to the [M+Na]+ formation mechanism. These data indicate that a sensitivity enhanced quantitative analysis using [M+A+H]+ could be a feasible approach for compounds generating [M+Na]+.
authors.affiliation: Development Research Center, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 2-17-85 Juso-Honmachi, Osaka 532-8686, Japan. Teshima_Kouichirou@takeda.co.jp
authors.forename: Koichiro
authors.initials: K
authors.lastname: Teshima
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yoneyama
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kondo
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000588:Amines / Q000032:analysis* / Q000737:chemistry; D003511:Cyclohexanols / Q000737:chemistry*; D005240:Feasibility Studies; D007477:Ions / Q000737:chemistry; D000432:Methanol / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D012964:Sodium / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry
chemical_list: D000588:Amines; D003511:Cyclohexanols; D007477:Ions; D012996:Solutions; D014867:Water; D012964:Sodium; D019342:Acetic Acid; C008699:octylamine; D000432:Methanol