Simplified method for trace analysis of trifluoroacetic acid in plant, soil, and water samples using headspace gas chromatography

A simple and sensitive analytical procedure was developed to determine the concentration of trifluoroacetic acid (TFA) in plant, soil, and water sampl es. The analysis involves extraction of TFA by sulfuric acid and methanol f ollowed by derivatization to the methyl ester of TFA (MTFA). This is accomp lished within a single vial without complex extraction procedures. The high ly volatile MTFA is then analyzed using headspace gas chromatography. The s pike recovery trials from all media ranged from a low of 86.7% to a high of 121.4%. The relative standard deviations (RSDs) were typically below 10%, although some tests had higher RSDs due to low concentrations near the dete ctable limit. The minimum detectable limit (MDL) for the method was 34 ng/g for dry plant material, 0.20 ng/g for soil, and 6.5 ng/L for water, This i s the first practical method for low-level analysis of TFA in plants and so il, and it is a significant improvement over previous methods for TFA in wa ter.