The proposed method makes possible an accurate determination of calcium, magnesium and zinc in lubricating oil samples by FAAS. The sample preparation is very simple and fast, not requiring
any equipment for homogenization or agitation. These features, allied to the higher stability of the standard and sample in the three-component solution and the possibility of using aqueous inorganic standards for calibration, makes the proposed method highly suitable for routine application. Therefore, it is an excellent alternative for monitoring the quality of lubricating oils within the Brazilian PMQL.