Rationale

This work item proposes the addition of a third Test Method C to ASTM D5708 to provide an alternative sample preparation procedure based on microwave-assisted acid digestion. The current standard does not include a method suitable for samples that require more efficient or complete decomposition. The inclusion of Test Method C will improve analytical accuracy and consistency for complex crude oil and residual fuel matrices, expand the applicability of the standard, and align with modern laboratory practices that utilize microwave digestion techniques.