The determination of wear metals in used lubricating oils

The determination of wear metals in used lubricating oils 

The method is applicable to the determination of Al, Ag, Cr, Cu, Fe, Ni, Si, Sn, Mg, Pb and Zn in used lubricating oils and may also be applicable to other elements of interest. Samples are diluted with MIBK and compared with organometallic standards in MIBK. Limits of detection will range from approximately 0.1/igml-1 for elements such as Zn and Cu, approximately 1 pgml-1 for elements such as Sn and Al and greater for Si. 

Pipette 5 ml of the used lubricating oil, which has been previously agitated, into a 25 ml volumetric flask and make up to the mark with MIBK. Shake well to dissolve and homogenise. 

Using either commercially available standards or those prepared as described in Section III, prepare calibration standards by dilution with MIBK. Choose a concentration range for each element which exhibits an approximately linear response. This will vary from instrument to instrument but as 

Prepare at least four calibration standards, including the blank, to cover the chosen concentration range. Prepare the calibration standards as required for use do not store. 

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