Elemental analysis of automobile engine lubrication oil using in-air PIXE

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2025-02, Vol.559, p.165601, Article 165601
• Main Authors: Saitoh, Katsumi, Tsuchida, Hidetsugu, Miwa, Misako, Toyama, Sho, Matsuyama, Shigeo
• Format: Article
• Language: English
• Subjects: Automobile engine lubrication oil; Automobile exhaust particles; Automobile tailpipe emissions; Elemental analysis; in-air PIXE; Metal particles
• ISSN: 0168-583X
• DOI: 10.1016/j.nimb.2024.165601

•The elemental components contained in automobile engine lubricating oil were analyzed using in-air PIXE.•Elemental constituents present in automobile engine lubricating oil were identified.•The presence of zinc dialkyldithiophosphate (ZnDTP) was confirmed from the concentration balance of P, S, and Zn in unused and used engine lubricating oils. To identify the elemental characteristics of engine lubricating oil-derived particles emitted from automobiles, we established an elemental analysis technique for engine lubricating oils using the in-air PIXE method, and conducted elemental analysis of unused and used engine lubrication oils, which revealed that S and Ca found in the internal standard base oil Sc 2000 wt-ppm (CONOSTAN®) and In 1000 wt-ppm (CONOSTAN®) were detected in addition to P, Fe and Zn, while K was detected only in the unused engine oil. The concentration balance of P, S, and Zn in the unused and used engine oil confirmed the presence of zinc dialkyldithiophosphate (ZnDTP), which is added to engine lubricating oil as a friction modifier and antioxidant. These results are useful in characterizing the elemental composition of particles derived from engine lubricating oils.