Analysis of exempt paint solvents by gas chromatography using solid-phase microextraction

Acetone, methyl acetate, and parachlorobenzotrifluoride (PCBTF or Oxsol? 100) have been exempted as VOC solvents by the U.S. Environmental Protection Agency. In measuring coating VOC content, separate methods for determining exempt solvents are required. One such method utilizes solid-phase microextraction (SPME) to sample the headspace of solvent-based coatings to which the surrogates acetone-d6, methyl acetate-d3, and/or metachlorobenzotrifluoride have been added. The sampled exempt coating solvents are thermally desorbed and analyzed using gas chromatography with flame ionization or mass spectral detection. The SPME headspace method has also been used to analyze MEK, butyl acetate, tert-butyl acetate, toluene, and xylene in solventborne coatings, and alcohols in waterborne systems. This paper presents the results obtained for acetone and toluene in a large number of aerosol paints. Additionally, the results from a round-robin study for acetone, methyl acetate, and parachlorobenzotrifluoride in commercial solvent-based coatings are reported.