Question on Incremental Sampling Methodologies

Ask the Expert Question:
One of the main tenants of the Incremental Sampling Methodologies approach is the analysis of a larger analytical subsample. For organic analysis, this doesn't seem to be a problem, but it is for metals. The digestion blocks that are the norm in environmental labs basically fix the analytical sample at 1 or maybe 2 grams. In fact, the official digestion methods are only validated for these small sample sizes. Is pulverization the only way to really get around the limitation on the analytical subsample size?

Experts Response:
You are correct that using large subsamples is a common part of Incremental Sampling Methodology (ISM). For organics using 10-30 g is already the norm so this isn't really a change for organic extractions. As you point out most metals digestion methods are optimized for 1-2 g aliquots. There are two common ways to address this limitation.