Standard-compliant lubricant analysis

Industrial lubricants have a lot of crucial functions. Amongst others, they reduce friction, transfer heat, transmit power, protect against wear, and prevent corrosion. Lubricant reliability relies on fast, precise and accurate analysis that complies with international standards.

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Hydroxyl value in lubricants

Oil drop
The hydroxyl number (HN) indicates the amount of KOH in mg corresponding to the hydroxyl groups in 1 g sample. It is a straightforward and precise parameter to monitor degradation processes. In ester-based lubricants, the HN indicates the degree of esterification.
We offer you a titration system for the fully automated determination of the hydroxyl number according to ASTM E-1899 and DIN EN ISO 4629-2. The method requires no boiling under reflux or other sample preparation steps. The method is a major benefit for laboratories that have to analyze a great number of samples per day.


Water determination

Petrochemical plant
The additives in lubricants can react with KF reagents and falsify the result. In a KF drying oven, a stream of dry carrier gas transfers the expelled water into the titration cell. Since the sample itself does not come into contact with the KF reagent, interfering side reactions and matrix effects can be excluded. The correct heating temperature lies below the decomposition temperature of the sample and is determined in preliminary tests.


Oxidation stability

Biolubricant overlay chromatogramm
Easily biodegradable lubricants can also be manufactured from natural fats and oils. Like the raw material, these products are also susceptible to oxidation.



Petrochemical plant
In lubricating oils, near-infrared spectroscopy (NIRS) is a viable tool for analyzing the content of aromatics, nitrogen and oil, and polycyclic aromatic hydrocarbons (PAHs). Further parameters are distillation analysis, flash point, pour point as well as density and viscosity.

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Testimonial: OELCHECK GmbH

"What I am really enthusiastic about is that together with Metrohm we have successfully improved and even developed many new methods."

OELCHECK GmbH is one of Germany’s leading laboratories for the analysis of lubricants and oils of all kinds. Automated solutions from Metrohm for the determination of TAN and TBN as well as water content according to Karl Fischer make sure that results are always in time with the customers – even when the workload is several thousand samples per day.

Standard-compliant lubricant analysis

Parameters Standard Matrix
pH DIN 51369
Testing of cooling lubricants – Determination of
the pH value of water-mixed cooling lubricants
Initial pH
ASTM D7946
Initial pH of lubricants
Base number ASTM D4739
ASTM D2896
Lubricants, petroleum products
Acid number ASTM D664
DIN EN 12634
ASTM D8045
Lubricants, petroleum products
Acidity and alkalinity IP 37 Lubricating grease
Hydroxyl number ASTM E1899
DIN EN ISO 4629-2
Lubricants, petroleum products
Water content ASTM E1064
ASTM D6304
ASTM D1533
Lubricating oil, crude oil, solvents
Lubricating oil, petroleum products
Insulating oil (liquid)