ASTM D7303 - 17 - Standard Test Method for Determination of Metals in Lubricating Greases by Inductively Coupled Plasma Atomic Emission Spectrometry

ASTM D7303 - 17

Standard Test Method for Determination of Metals in Lubricating Greases by Inductively Coupled Plasma Atomic Emission Spectrometry

Status : Current   Published : June 2017



1.1 This test method covers the determination of a number of metals such as aluminum, antimony, barium, calcium, iron, lithium, magnesium, molybdenum, phosphorus, silicon, sodium, sulfur, and zinc in unused lubricating greases by inductively coupled plasma atomic emission spectrometry (ICP-AES) technique.

1.1.1 The range of applicability for this test method, based on the interlaboratory study conducted in 2005, 2 is aluminum (10 to 600), antimony (10 to 2300), barium (50 to 800), calcium (20 to 50 000), iron (10 to 360), lithium (300 to 3200), magnesium (30 to 10 000), molybdenum (50 to 22 000), phosphorus (50 to 2000), silicon (10 to 15 000), sodium (30 to 1500), sulfur (1600 to 28 000), and zinc (300 to 2200), all in mg/kg. Lower levels of elements may be determined by using larger sample weights, and higher levels of elements may be determined by using smaller amounts of sample or by using a larger dilution factor after sample dissolution. However, the test precision in such cases has not been determined, and may be different than the ones given in Table 1.

TABLE 1 Precision of Grease Analysis

Note 1:  X is the mean concentration in mg/kg.

[This table has been removed.]

1.1.2 It may also be possible to determine additional metals such as bismuth, boron, cadmium, chromium, copper, lead, manganese, potassium, titanium, etc. by this technique. However, not enough data is available to specify the precision for these latter determinations. These metals may originate into greases through contamination or as additive elements.

1.1.3 During sample preparation, the grease samples are decomposed with a variety of acid mixture(s). It is beyond the scope of this test method to specify appropriate acid mixtures for all possible combination of metals present in the sample. But if the ash dissolution results in any visible insoluble material, the test method may not be applicable for the type of grease being analyzed, assuming the insoluble material contains some of the analytes of interest.

1.2 Elements present at concentrations above the upper limit of the calibration curves can be determined with additional appropriate dilutions of dissolved samples and with no degradation of precision.

1.3 The development of the technique behind this test method is documented by Fox. 3

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5  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. Specific warning statements are given in Sections 8 and 10.

1.6  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.

Standard NumberASTM D7303 - 17
TitleStandard Test Method for Determination of Metals in Lubricating Greases by Inductively Coupled Plasma Atomic Emission Spectrometry
Publication Date01 June 2017
Normative References(Required to achieve compliance to this standard)No other standards are normatively referenced
Informative References(Provided for Information)No other standards are informatively referenced
Descriptors Additive elements, Aluminum, Antimony, Barium, Calcium, Emission spectrometry, Grease, ICP, Inductively-coupled plasma emission spectrometry, Internal standard, Iron, Lithium, Lubricating grease, Magnesium, Molybdenum, Phosphorus, Silicon, Sodium, Sulfur, Zinc
File Size104 KB

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