1.1 This practice is suitable for testing the homogeneity of metals, either in solid or powdered form, and finely ground oxide materials that are intended for use as reference materials in X-ray emission, or optical emission spectroscopy, or both. The criteria for acceptance of the test specimens as reference materials, however, must be previously determined by the user for meeting his specific requirements.

1.2 The procedure is designed primarily for testing specimens by X-ray emission spectrometry or optical emission spectroscopy, or both. However, the practice could be easily adapted for use with other instrumental techniques such as atomic absorption spectrophotometry.

1.3 This procedure can be applied to one or more elements in a specimen provided the signal-to-background ratio is not a limiting factor.

1.4 This practice includes one method, if desired, to correct for systematic or periodic (sinusoidal) drift in the instrument with time through the use of a control reference material.

Note 1-Caution: If serious drift occurs (for example, unstable power supply, X-ray tube, etc.) erroneous conclusions may be obtained from the data analysis.

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.