In the case of the ethanol production plant, GC analysis is used to determine the total amount of denaturant added to the final ethanol product prior to shipment. This analysis is required in certain ethanol markets. The denaturant, being a petroleum distillate product, can contain hundreds of different compounds. The GC analysis for ASTM D5501 certification measures the amount of methanol, ethanol, and total amount of denaturant as area percents. These area percents are corrected, per the ASTM method, to give corrected volume percentages for these materials.