The content and ratio of metal elements V and Ni in crude oil play an important role in understanding the characterizing depositional environment and organic matter types of crude oil. However, in the process of crude oil refining, V and Ni, as harmful metal elements in the catalytic Cracking process of crude oil, will reduce the activity of the catalyst, and even lead to poisoning of the catalyst and serious corrosion of equipment. Before refining, V and Ni must be removed from the crude oil. In addition, V and Ni are mutagenic and carcinogenic, and it is becoming increasingly important to identify or monitor the Potential danger of V and Ni in crude oil entering the environment. Therefore, conducting highly sensitive and accurate determination of V and Ni content in crude oil is of great significance. This paper proposes a new strategy for determining V and Ni in crude oil by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). ICP-MS/MS directly analyzes the crude oil sample after diluting aviation kerosene. For the spectral interferences of V and Ni, in the MS/MS mode, the reaction gas mixture NH3/He/H2 is composed of NH3/He (He is the buffer gas), and H2 is used as the reaction gas. Based on the fact that V+ does not react with NH3/He/H2, but the interfering ions of V+ react with NH3/He/H2, the on-mass method was used to eliminate the interference, and V- was selected for determination. Based on the mass shift reaction between Ni+ and NHj/He/ H2, the interference was eliminated by the mass shift method, and the interference-free Cluster ion Ni(NH3)f was selected for determination. By comparing it with the NH3/He reaction mode, it is found that for the determination of V, adding H2 as a reaction gas can quickly remove the interference of large ions and cooperate with NH3 to eliminate the interference of oxide ions. For the determination of Ni, adding H2 as reaction gas can promote the formation of fully hydrogenated adducts (—NH3), thus increasing the yield of NKNHs.)^. In the NH3/He/H2 reaction mode, the background equivalent concentration (BEC) of V and Ni is lower, the sensitivity of Ni is higher, and the limit of detection (LOD) of V and Ni is as low as 0. 83 and 3. 76 ng • kg-1, respectively. The limit of quantification (LOQ) is 2. 77 and 12. 5 ng • kg-1, respectively. The accuracy and precision of the method were evaluated by analyzing the Standard reference material NIST SRM 1634c and the spiked recovery experiment, respectively. The results showed that the method's determination results were consistent with the certified values of the Standard reference material. The spiked recoveries of V and Ni were 97. 7% and 103%, respectively, and the relative Standard deviation (RSD) was 1. 8% and 1. 9%, respectively. The developed method avoids the complicated sample pretreatment process and has the characteristics of simple and rapid Operation, with high sensitivity, accuracy, and good precision. It is suitable for detecting V and Ni in crude oil and can provide a theoretical basis for removing V and Ni in the deep processing of crude oil. © 2025 Science Press. All rights reserved.
