Electron-capture gas chromatography of sulphonamides after extractive alkylation

The rate of extractive alkylation of 24 structurally related sulphonamides has been studied with respect to the alkylating agent and organic solvent. The reaction rate is given by the time for quantitative alkylation calculated from the observed first-order rate constant with 0.1 M tetrabutylammonium (pH 10) as the aqueous phase. The highest reaction rate were obtained with methyl iodide and pentafluorobenzyl bromide as reagents and methylene chloride and methyl isobutyl ketone as organic solvents. The minimum detectable concentration of the N1-methyl derivatives with electron-capture detection was about 10−15 mole/sec.