Frequently Asked Questions About TPH Analytical Methods for Crude Oil TPH Methods: Approximate Carbon Ranges Purgeable/Volatile/Gasoline Range, Modified 8015, Purge and Trap, GC Diesel Range, Modified 8015, Extraction, GC 418.1, Modified 418.1: Extraction, IR C 2 C 4 C 6 C 8 C 10C 12C 14C 16C 18C 20C 22C 24C 26C 28C 30 Gasoline Diesel Fuel ...