For a number of years we have used in our laboratory a simple extension to light elements of the classical ClifF-Lorimer approach using stoichiometric compound standards containing pairs of heavier elements to determine independently the EDS detector sensitivity contribution to quantitative analysis in the AEM. It is now also extended to direct light element LVEDS analysis in the SEM at low voltage (<5kV). This approach may be more practical, accessible and easily reproducible for routine use than the elegant custom thin film fabrications reported by Egerton, but the latter method has other substantial advantages, including well defined thicknesses, in the most sophisticated applications. As the types of advanced materials have expanded to include ceramics and polymers the requirements for analysis have also changed. In many cases the light elements are now the majority species in advanced materials and the corrections based on older standards are huge; and therefore inevitably rather limited in accuracy.