A Comparison of Methods to Determine Benzene in Gasoline Boiling Range Material

Several chromatographic methods are compared for the determination of benzene in a set of 200 samples containing gasoline boiling range material. These methods included ASTM D 3606, a liquid chromatographic method, and a multicolumn PIONA (paraffins, isoparaffins, aromatics, naphthalenes, and olefins) method. In addition, a coupled capillary method is evaluated for a smaller set of samples. Although a small bias is detected among these methods, the extent of disagreement among methods is not large. For example, a least-squares fit of D 3606 results (x-axis) against LC results (y-axis) gives a slope of 0.99 and an intercept of -0.03 wt% benzene. In this evaluation, the repeatability of D 3606 is approximately three times better than that of the LC method.