Elemental Analysis in Oil — ASTM D5185 / IP 501 / ICP-OES

What Is Metals?

Elemental analysis in oil and fuel is the determination of metal and metalloid concentrations in the sample. The results are interpreted in three groups: WEAR METALS (iron, copper, chromium, lead, aluminium, tin), POLLUTANTS (silicon, sodium, potassium, boron) and ADDITIVE ELEMENTS (zinc, phosphorus, calcium, magnesium, molybdenum).

Purpose of Metals

The aim is to detect which component in the machine is worn, to identify the contaminant entering from outside, and to monitor whether the additive package is exhausted.

Which Products Is Metals Applied To?

Used engine and gear oils
Hydraulic and turbine oils
Residual marine fuels
Crude oil and refinery flows
New oil additive validation samples

In Which Sectors Is Metals Used?

Oil & GasPetrokimyaEnergyAutomotiveMaritimeIndustrial Equipment

Standards Related to Metals

ASTM D5185 (Elementary analysis in oil with ICP-OES)
IP 501 (metal analysis in fuel — ICP)
IP 470 (aluminum and silicon)
ASTM D6595 (RDE spektrometri)
ASTM D7111 (element in middle distillates with ICP)

Metals Conditions

Particle size limit: ICP methods do not see large wear particles clearly; Larger particles require separate technique
Sample preparation: Dilution with solvent or solubilization with acid
Reference: The additive element profile of the new oil is required for comparison
Unit: mg/kg (ppm)

Equipment for Metals

ICP-OES
RDE spektrometre
Microwave digestion system
Analytical balances and dilution devices

Sample Requirements for Metals

Clean sample cup and consistent sample point
New oil reference sample must be provided
Machine type, oil type and service period must be declared
The sample must be homogenized

Duration of Metals

ICP measurement is fast; multi-element analysis is performed in a single run and the result is usually reported within a few business days.

Metals Procedure

1The sample is homogenized and weighed.
2It is diluted with solvent or solubilized with acid.
3An internal standard is added.
4Element concentrations are measured by ICP.
5Accuracy is confirmed with a control sample.
6The results are interpreted in wear, pollutant and additive groups.

Metals Acceptance Criteria

The acceptance criteria for fuels are the metal limits in the specification (such as aluminum + silicon in marine fuel). There is no fixed limit on used oil; The evaluation is based on the new oil reference and trend, based on the equipment manufacturer's thresholds.

Evaluation of Results

The element pattern indicates the source: if iron and chromium increase together, it may mean cylinder/ring, copper and tin bearing, silicon dust ingress, sodium and boron coolant leakage. The particle size limit of ICP methods is important: large particles formed in severe wear cannot be measured accurately, so ferrography or particle counting is used as a complement.

Metals Report

Sample description, machine and service information
Applied standard and measurement technique
Results by element (mg/kg)
New oil reference profile
Wear, pollutant and additive group comments
Trend assessment

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Fuel and LPG market technical regulations (EPDK)
EU 2009/30/EC (fuel quality directive)
Communiqués on the placing of lubricating oils on the market

Petroleum, Fuel and Oil Analysis — What Does This Testing Field Cover?

The section below describes the field that the Metals test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Petroleum, fuel and oil analysis determines whether a fluid meets its specification and how it behaves in use. Standards in this field consist largely of ASTM and EN publications, with a separate method defined for each parameter.

What distinguishes this family is that product specifications are written as PARAMETER LISTS. Specifications such as EN 590 (diesel), EN 228 (petrol), EN 14214 (biodiesel) and ISO 8217 (marine fuels) state for each parameter both the limit and the method by which that limit is to be measured. If the method changes the result may change too; the specification therefore binds the method as well, and the use of an "equivalent method" is possible only where the specification allows it.

On the fuel side, parameters describe three different properties of the product. Physical properties (density, viscosity, distillation curve, pour point, cloud point) determine pumpability and cold weather behaviour. Combustion properties (cetane number, octane number, calorific value) indicate performance in the engine. Contaminant and stability parameters (sulphur, water, sediment, oxidation stability, copper strip corrosion) affect both emissions and storage life.

Oil analysis is carried out for two different purposes and the two must not be confused. Analysis of NEW oil verifies the conformity of the product to its specification: viscosity index, additive content, flash point. Analysis of USED oil, by contrast, is done to read the condition of the machine — elemental analysis shows wear metals (iron, copper, chromium, aluminium), water and fuel contamination point to leaks, and oxidation and acid number determine the remaining life of the oil.

Used oil analysis is therefore a PREDICTIVE MAINTENANCE tool. The trend of samples taken at regular intervals is followed; it is the trend rather than a single result that is meaningful. Iron levels climbing over the course of months allow intervention before a failure occurs.

Marine fuels are the most active sub-body of the field. The global tightening of sulphur limits has brought new blended fuels onto the market; for these fuels stability, compatibility (whether two fuels form deposits when mixed) and catalytic fines content have become critical parameters.

Sampling is part of the result in this family too. A sample taken from the bottom of a tank shows different water and sediment content from one taken from the upper level; in commercial deliveries the sampling point and method are set by contract.

Method groups in this field

Physical properties
Density (oscillating U-tube and hydrometer), kinematic viscosity, distillation, pour and cloud point, flash point.
Combustion properties
Cetane number and cetane index, research and motor octane number, calorific value.
Sulphur and elements
Sulphur by UV fluorescence and XRF; elemental analysis and additive content by ICP.
Stability and corrosion
Oxidation stability, copper strip corrosion, water and sediment, filter blocking tendency.
Composition analysis
Boiling range distribution by gas chromatography, hydrocarbon types (FIA), benzene and aromatics content, fatty acid methyl ester content.
Used oil
Wear metals, contamination (water, fuel, soot), oxidation, acid and base number, change in viscosity.

Commonly confused in this field

The specification binds the method as well; a result measured by a different method may not be accepted for specification conformity.
A single result on used oil is not meaningful; the decision is made on the trend.
The sampling point determines the result; the tank bottom and the upper level show different water and sediment.
The cetane index is a calculated value and is not the same thing as a measured cetane number.
Fuels blended with biodiesel behave differently in terms of storage life and microbial growth; classical diesel parameters are not sufficient.
Mixing marine fuels from different sources can cause deposits; compatibility is assessed separately.

Which decisions these results support

Conformity of a fuel lot to specification and commercial delivery
Predictive maintenance decisions based on used oil analysis
Determining parameters for customs and tax classification
Quality verification after storage, blending and transport
Compliance with sulphur limits under emissions legislation

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Frequently Asked Questions About Metals

The iron value is normal but there is noise in the machine. Why does the analysis not show it?

ICP methods reliably measure only small particles. For severe wear that produces large particles, the values may be misleadingly low; In this case, ferrography or particle counting should be performed.

Why are additive elements monitored?

The decrease in elements such as zinc, phosphorus and calcium indicates that the additive package is exhausted. Additionally, an unexpected additive profile indicates that the wrong oil has been added.