EXPLANATION
When fuels are combusted, vanadium present in the fuel can form corrosive compounds. The value of crude oils can be determined, in part, by the concentrations of nickel, vanadium, and iron. Nickel and vanadium present at trace levels in petroleum fractions can deactivate catalysts during processing. These tests provide a means of determining vanadium, nickel, and iron, in crude oils and residual fuels by inductively coupled plasma atomic emission spectrometry. These test methods complement Test Method ASTM D1548, which determines vanadium by AAS and Test Method ASTM D5863, which determines the same elements by AAS. Typically lower limits of quantitation by these test methods are a few tenths of mg/kg.
TEST SUMMARY
Test Method A - The sample is dissolved in an organic solvent to make a 10 % m/m sample solution. This is analyzed by ICPAES using organometallic calibration standards.
Test Method B - The sample is decomposed with sulfuric acid. The residual carbon is burned off in a muffle furnace, and the inorganic residue is dissolved in dilute nitric acid. This solution is analyzed by ICPAES using aqueous calibration standards.
TEST PRECISION
Based on the analysis of NIST samples, there was no bias for both of these test methods for vanadium and nickel. The test for iron could not be determined.