1.1 ,This test method covers the determination of total nonaromatic hydrocarbons and monocyclic aromatic hydrocarbons in benzene, toluene, ethylbenzene, p-xylene, o-xylene, styrene and mixed xylenes by gas chromatography. The purity of benzene, toluene, ethylbenzene, p-xylene, o-xylene, styrene and mixed xylenes is also calculated. Similar test methods, using the internal standard calibration technique and the external standard calibration technique, are Test Methods D2360, D3797, D4492, D5060, D5135, D5917, and D6563 respectively.