Development of an accelerated artificial ageing method for the characterization of degradation products of antioxidants in lubricants by mass spectrometry

Abstract

The understanding of ageing mechanisms of antioxidants in base oils is indispensable for the development of improved lubricants. In this study, a novel artificial ageing method based on the application of peroxide as oxidant is presented for improved monitoring of thermo-oxidative degradation processes in combination with mass spectrometry. Model oils containing aminic and phenolic antioxidants were aged and chemical structures of their oxidation products were elucidated by ultrahigh performance liquid chromatography and electrospray ionization high resolution (Orbitrap) mass spectrometry. Additionally, synergistic mixtures of four antioxidants were investigated, because the formation of condensed molecules from amines and phenols would have a major influence on the antioxidant potential but could not be detected in the bulk lubricant.

Keywords

Tribochemistry antioxidants lubricants artificial ageing UHPLC electrospray ionization orbitrap mass spectrometry

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References

Dong

Migdal

Antioxidants. In: Rudnick

(ed). Lubricant additives: Chemistry and application, 2nd ed. Boca Raton, FL, USA: CRC Press, 2009, pp. 3–50.

Gatto

Moehle

Cobb

et al.

Oxidation fundamentals and its application to turbine oil testing. J ASTM Int 2006; 3: 1–20.

Bartels

Bock

Braun

et al.

Lubricants and lubrication. Ullmann's encyclopedia of industrial chemistry, Online ed. Hoboken, NJ, USA: Wiley-VCH, 2003.

Kassler

Pittenauer

Doerr

et al.

Electrospray ionization and atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry of antioxidants applied in lubricants. Rapid Commun Mass Spectrom 2009; 23: 3917–3927.

Kassler

Pittenauer

Doerr

et al.

CID of singly charged antioxidants applied in lubricants by means of a 3D ion trap and a linear ion trap-Orbitrap mass spectrometer. J Mass Spectrom 2011; 46: 517–528.

de Hoffmann

Stroobant

. Mass spectrometry: Principles and applications, 3rd ed. Hoboken, NJ, USA: John Wiley & Sons, 2007.

Brenton

Godfrey

. Accurate mass measurement: terminology and treatment of data. J Am Soc Mass Spectrom 2010; 22: 1821–1835.

Gross

. Accurate masses for structure confirmation. J Am Soc Mass Spectrom 1994; 5: 57.

Makarov

Denisov

Kholomeev

et al.

Performance evaluation of a hybrid linear ion trap/Orbitrap mass spectrometer. Anal Chem 2006; 78: 2113–2120.

10.

Besser

Schneidhofer

Dörr

et al.

Investigation of long-term engine oil performance using lab-based artificial ageing illustrated by the impact of ethanolas fuel component. Tribol Int 2012; 46: 174–182.

11.

CEC L-48-A00: Oxidation stability of lubricating oils used in automotive transmissions by artificial ageing. CEC Working Group, Brussels, Belgium, 2007.

12.

DIN 51352: Testing of lubricants; determination of ageing characteristics of lubricating oils; increase of the Conradson carbon residue after ageing by passing air through the lubricating oil. Deutsches Institut für Normung, Berlin, Germany, 1985.

13.

DIN 51554: Testing of mineraloils; test of susceptibility to ageing according to Baader; part 1: purpose, sampling, ageing; part 2: testing at 110℃; part 3: testing at 95℃. Deutsches Institut für Normung, Berlin, Deutschland, 1978.

14.

ASTM D.4742-08e1: Standard test method for oxidation stability of gasoline automotive engine oils by thin-film oxygen uptake (TFOUT). ASTM International, West Conshohocken, PA, USA, 2008.

15.

Kassler

Pittenauer

Doerr

et al.

Reversed phase UHPLC-ESI-LIT-Orbitrap mass spectrometry of antioxidants (amines and phenols) applied in lubricants. Rapid Commun Mass Spectrom 2014; 28: 63–76.

16.

Besser C. Untersuchung der thermooxidativen Stabilität von Industrieschmierölen. Master Thesis, University of Vienna, Vienna, Austria, 2007.

17.

DIN 51453: Testing of lubricants; determination of oxidation and nitration of used motoroils; infrared spectrometric method. Deutsches Institut für Normung, Berlin, Germany, 2004.

18.

Oelcheck GmbH. Why does infrared spectroscopy sometimes come up short?www.oelcheck.de/en/knowledge-from-a-z/test-methods/oxidation-of-gas-engine-oils-oelchecker-spring-2013.html (accessed 27 January2014).

19.

Vulic

Vitarelli

Zenner

. Structure-property relationships: phenolic antioxidants with high efficiency and low colour contribution. Polym Degrad Stab 2002; 78: 27–34.

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