Separation and conductimetric detection of C1–C7 aliphatic monocarboxylic acids and C1–C7 aliphatic monoamines on unfunctionized polymethacrylate resin columns

The application of unfunctionized polymethacrylate resin (TSKgel G3000PWXL) as a stationary phase in liquid chromatography with conductimetric detection for C1–C7 aliphatic monocarboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, isovaleric acid, valeric acid, 3,3-dimethylbutyric acid, 4-methylvaleric acid, hexanoic acid, 2-methylhexanoic acid, 5-methylhexanoic acid and heptanoic acid) and C1–C7 aliphatic monoamines (methylamine, ethylamine, propylamine, isobutylamine, butylamine, isoamylamine, amylamine, 1,3-dimethylbutylamine, hexylamine, 2-heptylamine and heptylamine) was attempted with C8 aliphatic monocarboxylic acids (2-propylvaleric acid, 2-ethylhexanoic acid, 2-methylheptanoic acid and octanoic acid) and C8 aliphatic monoamines (1,5-dimethylhexylamine, 2-ethylhexylamine, 1-methylheptylamine and octylamine) as eluents, respectively. Using 1 mM 2-methylheptanoic acid at pH 4.0 as the eluent, excellent separation and relatively high sensitive detection for these C1–C7 carboxylic acids were achieved on a TSKgel G3000PWXL column (150 mm×6 mm i.d.) in 60 min. Using 2 mM octylamine at pH 11.0 as the eluent, excellent separation and relatively high sensitive detection for these C1–C7 amines were also achieved on the TSKgel G3000PWXL column in 60 min.