GLASS-CAPILLARY COLUMN GAS-CHROMATOGRAPHY OF CARBOXYLIC-ACIDS AFTER FLASH-HEATER TRIMETHYLSILYLATION

Glass capillary column gas chromatography has been used for quantitative and qualitative analyses of carboxylic acids. The acids are first converted into non-polar derivatives by flash-heater derivatization, to make them more suitable for gas chromatography. Benzoic, nicotinic, salicylic, acetylsalicylic and p-aminobenzoic acids were used as model substances, and reagents suitable for forming trimethylsilyl derivatives were studied. The method was successful for benzoic, nicotinic and salicylic acid with N,O-bis(trimethylsilyl)trifluoroacetamide as derivatization reagent. With acetylsalicylic acid some decomposition to salicylic acid was observed and with p-aminobenzoic acid two derivatives were occasionally formed. Calibration graphs in the concentration range 5-50 μg/ml and the linearity up to 300 μg/ml were evaluated. The relative standard deviation for the quantitative analyses was calculated for the different acids. © 1979.