Abstract
The effect of lanthanum chloride addition for iron content determination in crude oil samples prepared in 15% v/v HNO₃ and 5% v/v H₂SO₄, respectively, was studied. The results indicated that the addition of lanthanum chloride (0.5-1.0% m/v) serves as a releasing agent for iron determination in nitrate medium, whereas the absorption is depressed in sulfate medium and this depression is proportionally increased by increasing iron concentration in the range of 0.5-3.0 ppm.