Abstract
This report describes the application of purge-and-trap (P&T) gas chromatography/mass spectrometry (GC/MS) to analyze carboxylic acids (CAs) using esterification. The optimum analytical conditions were determined based on the esterification recoveries using 10 mmol L-1 of a CAs methanol solution. P&T sampling was carried out with a Curiepoint head-space sampler. The optimum instrumental conditions were: purging, 150°C for 10 min; trap temperature, -10°C; desorption, 358°C for 20 s. A comparison of pyrolysis (Py)-GC/MS, P&T-GC/MS, and solvent extraction-GC/MS was made based on conversions of the CAs into the corresponding CA methylesters. The merits of the P&T method for the other two methods were validated according to quantitative data, the coefficient of variation, and the lower limit of determination calculated from the standard deviation. As a result, we concluded that the P&T method is more useful than the pyrolysis and solvent extraction methods.
