Identification and quantification of additives in lubricants

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Mastering the Composition of Critical Lubricants

In the aerospace and nuclear sectors, lubricant composition determines the reliability of mechanical components, control of ageing and compliance with internal requirements. A formulation degradation, contamination, product mix-up or batch-to-batch variability can alter the performance properties of the fluid. Filab laboratory supports industrial companies in characterising the organic and mineral fractions of lubricants, comparing a sample with a reference and investigating non-conformities.

Additive Families Investigated

Investigations may target phenolic or aminic antioxidants, phosphorus- or sulphur-containing compounds with anti-wear and extreme-pressure functions, corrosion inhibitors, as well as detergent, dispersant or viscosity-modifying additives. Elements such as phosphorus, sulphur, zinc, calcium, magnesium or molybdenum may also provide useful indicators, depending on the formulation under investigation.

Separation and Molecular Characterisation Techniques

Gas or liquid chromatography, combined with suitable detectors and mass spectrometry, can be used to separate, identify and quantify many organic compounds. Sample preparation may include dilution, extraction or fractionation to minimise the influence of the lubricant matrix. These approaches are particularly relevant for the quantification of additives in lubricants and for comparing chemical profiles.

Comparing a Compliant Sample with a Suspect Sample

Comparative analysis of a new lubricant, a lubricant in service or a lubricant from a suspect batch makes it possible to objectively assess differences in composition. Filab laboratory can investigate additive depletion, the formation of degradation products, cross-contamination or the presence of unusual elements. The analysis plan takes into account the packaging, the sampling history and the availability of a reference sample.

Identifying and Quantifying Lubricant Additives

The identification and quantification of additives make it possible to determine the families of compounds present in an oil or grease: antioxidants, anti-wear agents, extreme-pressure agents, corrosion inhibitors, dispersants, detergents, viscosity modifiers, or antifoaming agents. The analytical strategy is defined according to the matrix, the compounds being sought, the expected concentrations, and the control objective. Filab laboratory draws in particular on its expertise in quantifying molecules by GC and LC to produce an interpretable result.

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Interpretation in Relation to the Formulation

The presence of a compound alone is not enough to determine its function or confirm product compliance. Filab laboratory places the results in context with the base oil, the available reference information and the relative levels measured. This approach supports quality control, comparative analysis and the investigation of formulation deviations.

Analysis of Elements and Inorganic Fractions

Elemental techniques complement molecular analysis by assessing elements associated with certain additive families or with contamination. Infrared spectroscopy can also help compare oils, monitor chemical changes or guide investigations. The analytical methods are tailored to the industrial question and the required limits of quantification.

Securing Industrial Decisions

Analytical results provide factual data to support a release, monitoring, batch change or supplier investigation decision. For highly demanding environments, the Filab laboratory adapts its support to the traceability constraints and control objectives specific to energy and nuclear analysis.

Preparing your analysis request

To frame the study, provide the type of lubricant, its application, the objective of the analysis, product and batch references, available quantities, sampling conditions and any comparison samples. Indicating suspected additives, specifications to be verified or expected thresholds helps guide the method. Contact the Filab laboratory to define the test plan, submit the samples and obtain a tailored analytical proposal.

Frequently asked questions

How can additives present in a lubricant be identified and quantified?

At Filab laboratory, the analysis begins by defining the requirement: compliance testing, batch comparison, contamination screening or ageing study. Separation and spectrometric techniques are then selected to identify the compounds and, when standards or a suitable method are available, quantify them.

Which additives can be identified in an industrial oil or grease?

The list of additives to be investigated is defined on a case-by-case basis. It depends on the type of lubricant, its application, the available documentation and the phenomenon being investigated. Targeted analysis can be supplemented by screening to guide the identification of unexpected compounds.

Which analytical techniques are suitable for quantifying additives in lubricants?

Depending on the requirement, Filab laboratory combines gas chromatography, liquid chromatography, mass spectrometry, infrared spectroscopy and elemental analysis. A targeted method is preferred to quantify a known compound, while a screening approach is used to characterise a profile or investigate unexpected substances.

How can a formulation deviation or lubricant ageing be investigated?

An effective investigation relies on comparison with a relevant reference and a clearly defined analytical question. At the Filab laboratory, observed deviations are documented using qualitative and quantitative results, then interpreted in light of the information available on the products and their use.

What information should be provided when requesting a lubricant analysis?

Information about the product, its history and the control objective is essential for selecting the analytical strategy. At the Filab laboratory, this preliminary discussion helps define the relevant analysis, sample requirements and expected level of reporting.