This test method covers a liquid-chromatographic procedure for the separation of some additives currently used in high-density polyethylene. These additives are extracted with cyclohexane prior to liquid-chromatographic separation. The ultraviolet absorbance (200 nm) of the compound(s) is measured; quantitation is performed using the internal standard method. Note 1 -There is no similar or equivalent ISO standard. The values stated in SI units are to be regarded as the standard. 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. Specific precautionary statements are given in Section 9.