Because there are so many different chemicals in crude oil and in other petroleum products, it is not practical to measure each one separately.
Chemicals that occur in TPH include hexane, benzene, toluene, xylenes, naphthalene, and fluorene, other constituents of gasoline, jet fuels, mineral oils, and of other petroleum products.
[1] Petroleum hydrocarbon ranges are monitored at various levels depending on the state and testing site.
VPH is also known as petrol (or gasoline) range organics (PRO or GRO) and includes hydrocarbons from C6-C10.
[3] The report evaluates critically various new methods replacing the old ones using banned ozone depleting substances.