Sampling
The process of selecting a small portion of material that genuinely represents the bulk being analysed.
Unit
g
In depth
Sampling is often the largest single source of error in an analysis, and no amount of instrumental precision can compensate for an unrepresentative sample. Bulk materials are sampled at many points, combined, then reduced by coning and quartering to a manageable laboratory sample.
Examples in the real world
Taking increments from many points across a railway wagon of ore before crushing and subdividing.