ASTM D6595-22

Standard Test Method for Determination of Wear Metals and Contaminants in Used Lubricating Oils or Used Hydraulic Fluids by Rotating Disc Electrode Atomic Emission Spectrometry

SIGNIFICANCE AND USE
5.1 Used Lubricating Oil—The determination of debris in used oil is a key diagnostic method practiced in machine condition monitoring programs. The presence or increase in concentration of specific wear metals can be indicative of the early stages of wear if there are baseline concentration data for comparison. A marked increase in contaminant elements can be indicative of foreign materials in the lubricants, such as antifreeze or sand, which may lead to wear or lubricant degradation. The test method identifies the metals and their concentration so that trends relative to time or distance can be established and corrective action can be taken prior to more serious or catastrophic failure.
SCOPE
1.1 This test method covers the determination of wear metals and contaminants in used lubricating oils and used hydraulic fluids by rotating disc electrode atomic emission spectroscopy (RDE-AES).  
1.2 This test method provides a quick indication for abnormal wear and the presence of contamination in new or used lubricants and hydraulic fluids.  
1.3 This test method uses oil-soluble metals for calibration and does not purport to relate quantitatively the values determined as insoluble particles to the dissolved metals. Analytical results are particle size dependent and low results may be obtained for those elements present in used oil samples as large particles.  
1.4 The test method is capable of detecting and quantifying elements resulting from wear and contamination ranging from dissolved materials to particles approximately 10 μm in size.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5.1 The preferred units are mg/kg (ppm by mass).  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2022
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.03 - Elemental Analysis

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D4057-95(2000) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 10-Apr-2000

Overview

ASTM D6595-22 is an internationally recognized standard test method for the determination of wear metals and contaminants in used lubricating oils and hydraulic fluids using Rotating Disc Electrode Atomic Emission Spectrometry (RDE-AES). Developed by ASTM International Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, this standard plays a crucial role in oil condition monitoring, providing fast, reliable detection of metals and contaminants that result from mechanical wear or external sources. By analyzing oils for specific elements, ASTM D6595-22 helps detect abnormal machine wear, lubricant degradation, or contamination before catastrophic failures occur, supporting proactive maintenance and operational efficiency.

Key Topics

• Purpose and Scope

  • Determines concentration of wear metals and contaminants in used oils and hydraulic fluids.
  • Employs RDE-AES technique for rapid, quantitative detection.
  • Effective for particles up to approximately 10 μm in size.
  • Results reported in mg/kg (ppm by mass) using SI units.
  • Does not quantify large insoluble particles accurately.

• Significance and Benefits

  • Key diagnostic tool in predictive maintenance programs for engines, turbines, and hydraulic systems.
  • Provides early warning signs of abnormal wear, allowing for corrective action.
  • Detects foreign substances such as antifreeze, sand, and dust that could degrade lubricants or machinery.
  • Enables trending of metal concentrations over time for improved decision making.

• Analytical Elements

  • Commonly measured metals include aluminum, chromium, copper, iron, lead, manganese, nickel, tin, titanium, vanadium, and zinc.
  • Contaminants such as silicon (dust/sand), sodium, potassium, and additives like calcium, magnesium, and phosphorus are also analyzed.

• Sampling and Repeatability

  • Emphasizes representative oil sampling following ASTM D4057 or ASTM D4177 procedures.
  • Requires homogenization of samples to ensure accurate and repeatable results.
  • Includes guidelines on calibration, quality control, and equipment maintenance.

Applications

• Industrial and Automotive Maintenance

  • Used by maintenance teams in fleets, heavy machinery, marine engines, and power generation to monitor wear and contamination.
  • Facilitates condition-based maintenance for hydraulic systems and gearboxes.

• Oil Analysis Laboratories

  • Standardizes testing procedures for lubricant analysis labs, ensuring consistency and comparability of results.

• Predictive Maintenance Programs

  • Incorporates trend analysis to identify potential failures early.
  • Supports maintenance schedule optimization and reduction of unexpected downtime.

• Quality Assurance in Lubricant Manufacturing

  • Used to verify the cleanliness and additive content of new and in-service lubricants.

Related Standards

• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products - establishes procedures for obtaining representative oil samples.
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants - reference for terms and definitions used in D6595-22.
• ASTM D4177: Practice for Automatic Sampling of Petroleum and Petroleum Products - offers alternative, automated sampling guidelines.

ASTM D6595-22 is recognized internationally and aligns with World Trade Organization (WTO) principles on standardization, making it a trusted reference for organizations focused on asset reliability, safety, and cost-effective maintenance of critical equipment. Its use is essential in oil analysis laboratories, reliability-centered maintenance, and industrial sectors worldwide where machinery performance and lubricant cleanliness are paramount.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6595 − 22
Standard Test Method for
Determination of Wear Metals and Contaminants in Used
Lubricating Oils or Used Hydraulic Fluids by Rotating Disc
Electrode Atomic Emission Spectrometry
This standard is issued under the fixed designation D6595; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
1.1 This test method covers the determination of wear 2.1 ASTM Standards:
metals and contaminants in used lubricating oils and used D4057 Practice for Manual Sampling of Petroleum and
hydraulic fluids by rotating disc electrode atomic emission Petroleum Products
spectroscopy (RDE-AES). D4175 Terminology Relating to Petroleum Products, Liquid
Fuels, and Lubricants
1.2 This test method provides a quick indication for abnor-
D4177 Practice for Automatic Sampling of Petroleum and
mal wear and the presence of contamination in new or used
Petroleum Products
lubricants and hydraulic fluids.
3. Terminology
1.3 This test method uses oil-soluble metals for calibration
and does not purport to relate quantitatively the values deter-
3.1 Definitions:
mined as insoluble particles to the dissolved metals.Analytical
3.1.1 For definitions of terms used in this test method, refer
results are particle size dependent and low results may be
to Terminology D4175.
obtainedforthoseelementspresentinusedoilsamplesaslarge
3.2 Definitions of Terms Specific to This Standard:
particles.
3.2.1 arc discharge, n—a self-sustaining, high current
density, high temperature discharge, uniquely characterized by
1.4 The test method is capable of detecting and quantifying
elements resulting from wear and contamination ranging from a cathode fall nearly equal to the ionization potential of the gas
or vapor in which it exists.
dissolved materials to particles approximately 10 µm in size.
3.2.2 check sample, n—a reference material usually pre-
1.5 The values stated in SI units are to be regarded as
pared by a laboratory for its own use as a calibration standard,
standard. No other units of measurement are included in this
as a measurement control standard, or for the qualification of a
standard.
measurement method.
1.5.1 The preferred units are mg/kg (ppm by mass).
3.2.3 contaminant, n—material in an oil sample that may
1.6 This standard does not purport to address all of the
cause abnormal wear or lubricant degradation.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2.4 counter electrode, n—either of two graphite electrodes
priate safety, health, and environmental practices and deter-
in an atomic emission spectrometer across which an arc or
mine the applicability of regulatory limitations prior to use.
spark is generated.
1.7 This international standard was developed in accor-
3.2.5 graphite rod electrode, n—a soft form of the element
dance with internationally recognized principles on standard-
carbon manufactured into the shape of a rod for use as a
ization established in the Decision on Principles for the
counter electrode in arc/spark spectrometers for oil analysis.
Development of International Standards, Guides and Recom-
3.2.6 profiling, n—to set the actual position of the entrance
mendations issued by the World Trade Organization Technical
slit to produce optimum measurement intensity.
Barriers to Trade (TBT) Committee.
3.2.7 standardization, n—the process of reestablishing and
correcting a calibration curve through the analysis of at least
two known oil standards.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.03 on Elemental Analysis. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2022. Published October 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2000. Last previous edition approved in 2017 as D6595 – 17. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6595-22. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6595 − 22
3.2.8 uptake rate, n—the amount of oil sample that is concentration they represent. Large particles may not be
physically carried by the rotating disc electrode into the arc for effectively transported by the rotating disk electrode sample
analysis. introduction system into the arc, nor will they be fully
vaporized by the spark.
3.2.9 wear metal, n—material resulting from damage to a
solid surface due to relative motion between that surface and a
7. Apparatus
contacting substance or substances.
7.1 Electrode Sharpener—An electrode sharpener is neces-
4. Summary of Test Method sary to remove the contaminated portion of the rod electrode
remainingfromthepreviousdetermination.Italsoformsanew
4.1 Wear metals and contaminants in a used oil test speci-
160° angle on the end of the electrode. Electrode sharpeners
men are evaporated and excited by a controlled arc discharge
are not required for instruments using a pre-shaped disc
using the rotating disk technique. The radiant energies of
electrode as the counter electrode.
selected analytical lines and one or more references are
collected and stored by way of photomultiplier tubes, charge-
7.2 Rotating Disc Electrode Atomic Emission Spectrometer,
coupled devices, or other suitable detectors. A comparison is a simultaneous spectrometer consisting of excitation source,
made of the emitted intensities of the elements in the used oil
polychromator optics, and a readout system. Suggested ele-
test specimen against those measured with calibration stan- ments and wavelengths are listed in Table 1. When multiple
dards.The concentrations of the elements present in the oil test
wavelengths are listed, they are in the order of preference or
specimen are calculated and displayed. They may also be desired analytical range.
entered into a data base for processing.
7.3 Heated Ultrasonic Bath (Recommended), an ultrasonic
bathtoheatandhomogenizeusedoilsamplestobringparticles
5. Significance and Use
into homogeneous suspension. The ultrasonic bath shall be
5.1 Used Lubricating Oil—The determination of debris in
used on samples containing large amounts of debris and those
used oil is a key diagnostic method practiced in machine that have been in transit or stored for 48 h or longer.
condition monitoring programs. The presence or increase in
concentration of specific wear metals can be indicative of the 8. Reagents and Materials
early stages of wear if there are baseline concentration data for
8.1 Base Oil, a 75 cSt base oil free of analyte to be used as
comparison.Amarkedincreaseincontaminantelementscanbe
a calibration blank or for blending calibration standards.
indicative of foreign materials in the lubricants, such as
8.2 Check Samples, An oil standard or sample of known
antifreeze or sand, which may lead to wear or lubricant
concentration which is periodically analyzed as a go/no-go
degradation. The test method identifies the metals and their
sample to confirm the need for standardization based on an
concentration so that trends relative to time or distance can be
allowable 610 % accuracy limit.
established and corrective action can be taken prior to more
serious or catastrophic failure. 8.3 Cleaning Solution, An environmentally safe, non-
chlorinated,rapidevaporating,andnon-filmproducingsolvent,
6. Interferences to remove spilled or splashed oil sample in the sample stand.
6.1 Spectral—Most spectral interferences can be avoided by
8.4 Disc Electrode, a graphite disc electrode of high-purity
judicious choice of spectral lines. High concentrations of graphite (spectroscopic grade). Dimensions of the electrodes
additive elements can have an interfering influence on the
shall conform to those shown in Fig. 1.
spectral lines used for determining wear metals. Instrument
8.5 Glass Cleaning Solution, capable of cleaning and re-
manufacturers usually compensate for spectral interferences
moving splashed oil sample from the quartz window that
during factory calibration. A background correction system,
protects the entrance lens and fiber optic. Isopropyl rubbing
which subtracts unwanted intensities on either side of the
alcohol or ammonia-based window cleaner has been found to
spectral line, shall also be used for this purpose. When spectral
be suitable for this purpose.
interferencescannotbeavoidedwithspectrallineselectionand
backgroundcorrection,thenecessarycorrectionsshallbemade
using the computer software supplied by the instrument manu-
TABLE 1 Elements and Recommended Wavelengths
facturer.
Element Wavelength, nm Element Wavelength, nm
6.2 Viscosity Effects—Differences in viscosity of used oil
Aluminum 308.21 Nickel 341.48
samples will cause differences in uptake rates. Internal refer-
Barium 230.48, 455.40 Phosphorus 255.32, 214.91
Boron 249.67 Potassium 766.49
ences of the instrument will compensate for a portion of the
Calcium 393.37, 445.48 Silicon 251.60
differences. In used oil applications, the hydrogen 486.10 nm
Chromium 425.43 Silver 328.07, 243.78
spectral line has become the industry standard for use as an
Copper 324.75, 224.26 Sodium 588.89, 589.59
Iron 259.94 Tin 317.51
internalreference.Withoutareference,trendeddataonusedoil
Lead 283.31 Titanium 334.94
will be adversely affected if the sample base stock has a
Lithium 670.78 Tungsten 400.87
different viscosity from the base line samples.
Manganese 403.07, 294.92 Vanadium 290.88, 437.92
Magnesium 280.20, 518.36 Zinc 213.86
6.3 Particulate—When large particles over 10 µm in size
Molybdenum 281.60
are detected, the analytical results will be lower than the actual
D6595 − 22
TABLE 2 Repeatability
10. Preparation of Test Specimen
NOTE 1—X = mean concentration in mg/kg.
10.1 Homogenization—Used oil samples may contain par-
Element Range, mg/kg Repeatability, mg/kg ticulate matter and, in order to be representative, must always
0.45
Aluminum 0.23–101 0.5419(X+0.57) be vigorously shaken prior to pouring a test specimen for
1.18
Barium 28–115 0.0694X
analysis.
0.56
Boron 0.14–120 0.4280(X+0.1028)
Calcium 3.7–11460 0.1106(X+2.184)
10.2 Ultrasonic Homogenization—Samples that have been
0.41
Chromium 0.18–152 0.7285(X+0.0557)
in transit for several days, idle in storage, or very viscous shall
0.85
Copper 0.47–100 0.1631(X+0.3459)
0.73
be placed in a heated ultrasonic bath to break up clusters of
Iron 4.8–210 0.3159 (X+0.0141)
0.34
Lead 0.43–101 1.062(X+0.6015)
particles and to bring them back into suspension. The samples
Magnesium 4.9–1360 0.1049X
shall be vigorously shaken after being in the ultrasonic bath
0.34
Manganese 0.3–117 0.7017(X+0.3534)
0.34
and prior to pouring a test specimen for analysis. The bath
Molybdenum 0.21–100 0.9978(X+0.4795)
0.40
Nickel 0.35–100 0.7142(X+0.3238)
temperature shall be at least 60 °C and the total agitation time
Phosphorus 52–2572 0.0761(X+14.76)
at least 2 min.
0.63
Potassium 0.35–247 0.4075(X+0.1154)
0.63
Silicon 3.2–142 0.4015(X+0.1692)
10.3 Specimen Holders—Used oil samples and oil standard
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6595 − 17 D6595 − 22
Standard Test Method for
Determination of Wear Metals and Contaminants in Used
Lubricating Oils or Used Hydraulic Fluids by Rotating Disc
Electrode Atomic Emission Spectrometry
This standard is issued under the fixed designation D6595; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of wear metals and contaminants in used lubricating oils and used hydraulic fluids
by rotating disc electrode atomic emission spectroscopy (RDE-AES).
1.2 This test method provides a quick indication for abnormal wear and the presence of contamination in new or used lubricants
and hydraulic fluids.
1.3 This test method uses oil-soluble metals for calibration and does not purport to relate quantitatively the values determined as
insoluble particles to the dissolved metals. Analytical results are particle size dependent and low results may be obtained for those
elements present in used oil samples as large particles.
1.4 The test method is capable of detecting and quantifying elements resulting from wear and contamination ranging from
dissolved materials to particles approximately 10 μm in size.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5.1 The preferred units are mg/kg (ppm by mass).
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.03 on Elemental Analysis.
Current edition approved May 1, 2017Oct. 1, 2022. Published May 2017October 2022. Originally approved in 2000. Last previous edition approved in 20162017 as
D6595 – 16.D6595 – 17. DOI: 10.1520/D6595-17.10.1520/D6595-22.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6595 − 22
2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
3. Terminology
3.1 Definitions:
3.1.1 burn, vt—in emission spectroscopy, to vaporize and excite a specimen with sufficient energy to generate spectral radiation.
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.1.2 calibration, n—the determination of the values of the significant parameters by comparison with values indicated by a set
of reference standards.
3.1.3 calibration curve, n—the graphical or mathematical representation of a relationship between the assigned (known) values
of standards and the measured responses from the measurement system.
3.1.4 calibration standard, n—a standard having an accepted value (reference value) for use in calibrating a measurement
instrument or system.
3.1.5 emission spectroscopy, n—measurement of energy spectrum emitted by or from an object under some form of energetic
stimulation; for example, light, electrical discharge, and so forth.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 arc discharge, n—a self-sustaining, high current density, high temperature discharge, uniquely characterized by a cathode
fall nearly equal to the ionization potential of the gas or vapor in which it exists.
3.2.2 check sample, n—a reference material usually prepared by a laboratory for its own use as a calibration standard, as a
measurement control standard, or for the qualification of a measurement method.
3.2.3 contaminant, n—material in an oil sample that may cause abnormal wear or lubricant degradation.
3.2.4 counter electrode, n—either of two graphite electrodes in an atomic emission spectrometer across which an arc or spark is
generated.
3.2.5 graphite disc electrode, n—a soft form of the element carbon manufactured into the shape of a disc for use as a counter
electrode in arc/spark spectrometers for oil analysis.
3.2.5 graphite rod electrode, n—a soft form of the element carbon manufactured into the shape of a rod for use as a counter
electrode in arc/spark spectrometers for oil analysis.
3.2.6 profiling, n—to set the actual position of the entrance slit to produce optimum measurement intensity.
3.2.7 standardization, n—the process of reestablishing and correcting a calibration curve through the analysis of at least two
known oil standards.
3.2.8 uptake rate, n—the amount of oil sample that is physically carried by the rotating disc electrode into the arc for analysis.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D6595 − 22
3.2.9 wear metal, n—material resulting from damage to a solid surface due to relative motion between that surface and a
contacting substance or substances.
4. Summary of Test Method
4.1 Wear metals and contaminants in a used oil test specimen are evaporated and excited by a controlled arc discharge using the
rotating disk technique. The radiant energies of selected analytical lines and one or more references are collected and stored by
way of photomultiplier tubes, charge-coupled devices, or other suitable detectors. A comparison is made of the emitted intensities
of the elements in the used oil test specimen against those measured with calibration standards. The concentrations of the elements
present in the oil test specimen are calculated and displayed. They may also be entered into a data base for processing.
5. Significance and Use
5.1 Used Lubricating Oil—The determination of debris in used oil is a key diagnostic method practiced in machine condition
monitoring programs. The presence or increase in concentration of specific wear metals can be indicative of the early stages of
wear if there are baseline concentration data for comparison. A marked increase in contaminant elements can be indicative of
foreign materials in the lubricants, such as antifreeze or sand, which may lead to wear or lubricant degradation. The test method
identifies the metals and their concentration so that trends relative to time or distance can be established and corrective action can
be taken prior to more serious or catastrophic failure.
6. Interferences
6.1 Spectral—Most spectral interferences can be avoided by judicious choice of spectral lines. High concentrations of additive
elements can have an interfering influence on the spectral lines used for determining wear metals. Instrument manufacturers usually
compensate for spectral interferences during factory calibration. A background correction system, which subtracts unwanted
intensities on either side of the spectral line, shall also be used for this purpose. When spectral interferences cannot be avoided
with spectral line selection and background correction, the necessary corrections shall be made using the computer software
supplied by the instrument manufacturer.
6.2 Viscosity Effects—Differences in viscosity of used oil samples will cause differences in uptake rates. Internal references of the
instrument will compensate for a portion of the differences. In used oil applications, the hydrogen 486.10 nm spectral line has
become the industry standard for use as an internal reference. Without a reference, trended data on used oil will be adversely
affected if the sample base stock has a different viscosity from the base line samples.
6.3 Particulate—When large particles over 10 μm in size are detected, the analytical results will be lower than the actual
concentration they represent. Large particles may not be effectively transported by the rotating disk electrode sample introduction
system into the arc, nor will they be fully vaporized by the spark.
7. Apparatus
7.1 Electrode Sharpener—An electrode sharpener is necessary to remove the contaminated portion of the rod electrode remaining
from the previous determination. It also forms a new 160° angle on the end of the electrode. Electrode sharpeners are not required
for instruments using a pre-shaped disc electrode as the counter electrode.
7.2 Rotating Disc Electrode Atomic Emission Spectrometer, a simultaneous spectrometer consisting of excitation source,
polychromator optics, and a readout system. Suggested elements and wavelengths are listed in Table 1. When multiple wavelengths
are listed, they are in the order of preference or desired analytical range.
7.3 Heated Ultrasonic Bath (Recommended), an ultrasonic bath to heat and homogenize used oil samples to bring particles into
homogeneous suspension. The ultrasonic bath shall be used on samples containing large amounts of debris and those that have been
in transit or stored for 48 h or longer.
8. Reagents and Materials
8.1 Base Oil, a 75 cSt base oil free of analyte to be used as a calibration blank or for blending calibration standards.
D6595 − 22
TABLE 1 Elements and Recommended Wavelengths
Element Wavelength, nm Element Wavelength, nm
Aluminum 308.21 Nickel 341.48
Barium 230.48, 455.40 Phosphorus 255.32, 214.91
Boron 249.67 Potassium 766.49
Calcium 393.37, 445.48 Silicon 251.60
Chromium 425.43 Silver 328.07, 243.78
Copper 324.75, 224.26 Sodium 588.89, 589.59
Iron 259.94 Tin 317.51
Lead 283.31 Titanium 334.94
Lithium 670.78 Tungsten 400.87
Manganese 403.07, 294.92 Vanadium 290.88, 437.92
Magnesium 280.20, 518.36 Zinc 213.86
Molybdenum 281.60
TABLE 2 Repeatability
NOTE 1—X = mean concentration in mg/kg.
Element Range, mg/kg Repeatability, mg/kg
0.45
Aluminum 0.23–101 0.5419(X+0.57)
1.18
Barium 28–115 0.0694X
0.56
Boron 0.14–120 0.4280(X+0.1028)
Calcium 3.7–11460 0.1106(X+2.184)
0.41
Chromium 0.18–152 0.7285(X+0.0557)
0.85
Copper 0.47–100 0.1631(X+0.3459)
0.73
Iron 4.8–210 0.3159 (X+0.0141)
0.34
Lead 0.43–101 1.062(X+0.6015)
Magnesium 4.9–1360 0.1049X
0.34
Manganese 0.3–117 0.7017(X+0.3534)
0.34
Molybdenum 0.21–100 0.9978(X+0.4795)
0.40
Nickel 0.35–100 0.7142(X+0.3238)
Phosphorus 52–2572 0.0761(X+14.76)
0.63
Potassium 0.35–247 0.4075(X+0.1154)
0.63
Silicon 3.2–142 0.4015(X+0.1692)
0.88
Silver 31–102 0.1523(X+1.2)
Sodium 3.6–99.6 0.1231(X−2.674)
0.45
Tin 30–139 0.6777(X+0.6578)
0.5
Titanium 6.8–103 0.5831(X+0.9304)
0.41
Vanadium 2.1–101 0.6389(X+0.8418)
0.87
Zinc 5.3–1345 0.2031(X+1.553)
8.2 Check Samples, An oil standard or sample of known concentration which is periodically analyzed as a go/no-go sample to
confirm the need for standardization based on an allowable 610 % accuracy limit.
8.3 Cleaning Solution, An environmentally safe, non-chlorinated, rapid evaporating, and non-film producing solvent, to remove
spilled or splashed oil sample in the sample stand.
8.4 Disc Electrode, a graphite disc electrode of high-purity graphite (spectroscopic grade). Dimensions of the electrodes shall
conform to those shown in Fig. 1.
8.5 Glass Cleaning Solution, capable of cleaning and removing splashed oil sample from the quartz window that protects the
entrance lens and fiber optic. Isopropyl rubbing alcohol or ammonia-based window cleaner has been found to be suitable for this
purpose.
8.6 Organometallic Standards, single or multi-element blended standards for use as the high concentration standard for instrument
standardization purposes or for use as a check sample to
...