ASTM D7214 Standard Test Method for Determination of the Oxidation of Used Lubricants by FT-IR Using Peak Area Increase Calculation
1. Scope
1.1 This test method covers the determination of the oxidation of used lubricants by FT-IR (Fourier Transform Infrared Spectroscopy). It measures the concentration change of constituents containing a carbonyl function that have formed during the oxidation of the lubricant.
1.2 This test method may be used to indicate relative changes that occur in an oil under oxidizing conditions. The test method is not intended to measure an absolute oxidation property that can be used to predict performance of an oil in service.
1.3 This test method was developed for transmission oils which have been degraded either in service, or in a laboratory test, for example a bulk oxidation test. It may be used for other in-service oils, but the stated precision may not apply.
1.4 The results of this test method may be affected by the presence of other components with an absorbance band in the zone of 1600 - 1800 cm(-1). Low PAI values may be difficult to determine in those cases. Section 6 describes these possible interferences in more detail.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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 and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance Techniques to Evaluate Analytical Measurement System Performance
E 131 Terminology Relating to Molecular Spectroscopy
E 1421 Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: Level Zero and Level One Tests
E 1866 Guide for Establishing Spectrophotometer Performance Tests
2.2 CEC Standard:
CEC L-48-A-00 Oxidation Stability of Lubricating Oils Used in Automotive Transmissions by Artificial Aging
3. Terminology
3.1 Definitions - For terminology relating to molecular spectroscopic methods, refer to Terminology E 131.
3.2 Definitions ofTerms Specific to This Standard:
3.2.1 carbonyl region, n - region of the FT-IR spectrum corresponding to the absorbance of compounds containing a carbonyl function. Depending on the nature of the carbonyl compounds, this region is usually located between approximately 1820 cm(-1) and 1650 cm(-1).
3.2.2 differential spectrum, n - FT-IR absorbance spectrum resulting from the subtraction of the fresh oil from the used oil.
3.2.3 PAI (peak area increase), n - area of the carbonyl region of the differential FT-IR spectrum, divided by the cell pathlength in millimetres. In this standard, PAI refers to a relative measurement of the oxidation of a used lubricant by FT-IR.
