This report describes certification of the Mw of SRM 2888, a polystyrene (PS), by light scattering. As supplemental numbers, the Mn by NMR end group analysis and the Mw, Mn and the MMD by MALDI-TOF-MS are also given. SRM 2888 was prepared commercially for NIST Polymers Division for use as a standard for Size Exclusion Chromatography and as a narrow distribution polymer standard with well-defined classical molecular mass moments for comparative studies by MALDI-MS. This material was specially prepared and characterized for well-defined end groups. After packaging of this material for future...