The use of oily pharmaceutical excipients became important to the use of some injectable drugs.1 Among the pharmaceutical excipients available for injectable drugs, some oily excipients such as soybean oil, castor oil, corn oil, and sesame oil are commonly used.1 However, oily excipients are not completely free of elemental impurity and the quality control is mandatory. In this way, the International Council for Harmonisation (ICH) classifies the elemental impurity according to their toxicities.2 Moreover, according to the ICH guideline Q3D, the quality control of class 1 (As, Cd, Hg, and Pb) and class 2A (Co, Ni, and V) is necessary in oily excipients used in the formulation of injectable drugs.2 Despite the necessity to determine class 1 and class 2A in oily excipients, some difficulties are related to the sample preparation step mainly due to the matrix complexity and the low levels of the analytes usually present in this kind of sample. In order to overcome these limitations, in the present study, a reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method was developed for further As, Cd, Pb, Co, Ni, and V determination in oily excipients by inductively coupled plasma mass spectrometry (ICP-MS) and Hg by cold vapor generation coupled with ICP-MS. The RP-DLLME method is based on the analytes extraction from the organic phase (oil sample) to an aqueous phase using a dispersant/extractant (alcohol/diluted acid solution) mixture. For the RP-DLLME procedure, a water-bath (Elmasonic P 120 H, Germany), capacity of 9 L and temperature control (up to 85 °C) was used. A certified reference oil material was used for recovery experiments. Corn oil was used for the development of the proposed method. Operational parameters, such as proportion of dispersant:extractant solvents (65:35 to 15:85% v/v), extractant solvent concentration and type (0.5 to 3.0 mol L-1 HNO3 and 4.0 to 10 mol L-1 HCl), extraction solution volume (1.0 to 2.0 mL), and centrifugation time (5 to 15 min) were evaluated. A green analytical metric was used to analyze the proposed method greenness. Suitable results were obtained by using 5 g of oily excipient, a mixture of dispersant (n-propanol) and extractant (3.0 mol L-1 HNO3 solution for As, Cd, Pb, Co, Ni, and V and 6.0 mol L-1 HCl solution for Hg) solvents with proportion of 50:50% (v/v) in 2 mL, 85 °C, and 10 min of centrifugation. Due to the use of a high sample mass (5 g), diluted extraction solutions, and low detection limits (ranged from 1 to 31 ng g-1) were obtained.