ASTM D5185 for additive elements, wear metals, contaminants and selected elements
ASTM D5185 Standard Test Method for Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils and Determination of Selected Elements in Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
9. Sampling
9.1 The objective of sampling is to obtain a test specimen that is representative of the entire quantity. Thus, take lab samples in accordance with the instructions in Practice D4057. The specific sampling technique can affect the accuracy of this test method.
10. Preparation of Apparatus
10.1 Instrument - Design differences between instruments, ICP excitation sources, and different selected analytical wavelengths for individual spectrometers make it impractical to detail the operating conditions. Consult the manufacturer's instructions for operating the instrument with organic solvents. Set up the instrument for use with the particular dilution solvent chosen.
10.2 Peristaltic Pump - If a peristaltic pump is used, inspect the pump tubing and replace it, if necessary, before starting each day. Verify the solution uptake rate and adjust it to the desired rate.
10.3 ICP Excitation Source - Initiate the plasma source at least 30 min before performing analysis. During this warm up period, nebulize dilution solvent. Inspect the torch for carbon build-up during the warm up period. If carbon build-up occurs, replace the torch immediately and consult the manufacturer's operating guide to take proper steps to remedy the situation.
NOTE 2 - Some manufacturers recommend even longer warm-up periods to minimize changes in the slopes of calibration curves.
10.4 Wavelength Profiling - Perform any wavelength profiling that may be called for in the normal operation of the instrument.
10.5 Operating Parameters -Assign the appropriate operating parameters to the instrument task file so that the desired elements can be determined. Parameters to be included are element, wavelength, background correction points (optional), interelement correction factors (optional), integration time, and internal standard correction (optional). Multiple integrations are required for each measurement, and the integration time is typically 10 s.
