Trace Metals Analysis in Petroleum Products by Atomic Absorption

Abstract

To provide information for customers who have regional environmental obligations, it was necessary to develop an analytical procedure to analyze for 25 metals in the range from 1 ppb to greater than 5 ppm in petroleum products. Atomic absorption is employed to determine 23 of the elements, namely: Al, Sb, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Pb, Mg, Mn, Mo, Ni, Na, Si, Sn, Ti, V, and Zn. The general procedure is to ash the appropriate amount of sample by absorbing liquid samples on magnesium sulfonate ash aid (Conostan, Conoash M) or potassium sulfonate. Add 5 drops of H₂SO₄, heat to white fumes, fire, and ash at 650°C. The sulfonated ash is dissolved in dilute acid to provide the aspiration solution. Recovery studies on aluminum, antimony, beryllium, cadmium, and lead in the microgram per gram range are presented.