ASTM D7040 Standard Test Method for Determination of Low Levels of Phosphorus in ILSAC GF 4 and Similar Grade Engine Oils by Inductively Coupled Plasma Atomic Emission Spectrometry
13. Analysis
13.1 Analyze the test specimen solutions in the same manner as the calibration standards (that is, same integration time, background correction points (required), plasma conditions, and so forth). Between test specimens nebulize dilution solvent for a minimum of 60 s.
13.2 When the concentration of any analyte exceeds the linear range of the calibration, prepare another test specimen by mixing the sample with base oil before adding diluent (refer to 11.2.1, for example). Then, reanalyze.
13.3 Analyze the check standard after every fifth test specimen solution. If any result is not within 5 % of the expected concentration, recalibrate the instrument and reanalyze the test specimen solutions back to the previous acceptable check standard analysis.
14. Quality Assurance/Quality Control (QA/QC) (Required)
14.1 Confirm the performance of the instrument and the test procedure by analyzing a QC sample. See Guide D6792 for guidance.
14.1.1 When QA/QC protocols are already established in the testing facility, these may be used to confirm the reliability of the test result.
14.1.2 When there is no QA/QC protocol established in the testing facility, Appendix X1 can be used as the QA/QC protocol.
14.2 Users ofthis test method are advised that in contractual agreements, one or more ofthe contracting parties can and may make Appendix X1 a mandatory practice.
