(Equivalent Test Methods: IP 407 and DIN 51391 T2)
TEST SUMMARY
This test method covers the determination of barium, calcium, phosphorus, sulfur, and zinc in unused lubricating oils at element concentration ranges of 0.03 to 1.0 % mass (0.01 to 2.0 % for sulfur). The range may be extended to higher concentrations by dilution of sample specimens. Additives may also be determined after dilution with base oil. Two different procedures are presented in this test method:
Procedure A: Internal Standard Procedure - Internal standards are used to compensate for inter-element effects of X-ray excitation and fluorescence.
Procedure B: Mathematical Correction Procedure - The measured X-ray fluorescence intensity for a given element is mathematically corrected for potential interference from other elements present in the sample.
A sample specimen is placed in the X-ray beam and the intensity of the appropriate fluorescence lines of barium, calcium, phosphorus, sulfur, and zinc are measured. Instrument response factors related to the concentration of standards enable the determination of the concentration of elements in the tested sample specimens. Enhancement or depression of the X-ray fluorescence of a given element by an interfering element in the sample may occur. This is corrected by internal standards in Procedure A, and by mathematical correction in Procedure B.
TEST PRECISION
