This column set (cat.# 118-D3606) conforms to the specifications established in ASTM method D3606 Procedure A for the quantitation of benzene and toluene in spark ignition fuel. Procedure A uses capillary columns in series with the sample passing through a nonpolar column first, followed by a second column that separates aromatic and nonaromatic compounds. A restrictor column is also used in the setup, which can be purchased separately. This capillary column set is recommended for determining benzene concentration in butanol-blended fuels.