Automated

headspace solid-phase microextraction (SPME) coupled with gas chromatography and flame ionization detection is used to determine the amounts of methanol and tetrahydrofuran (THF) in distillation residue samples from a proprietary chemical reaction. A 65-µm polydimethylsiloxane/divinylbenzene SPME fiber is used to perform the extractions. Optimized extraction conditions for each analyte are determined using a parts-per-million-level methanol in water standard and a parts-per-billion-level THF in water standard. The amount of methanol and THF in distillation residue samples is quantitated by both standard addition and external standard calibration curve. The two methods of quantitation are compared