Chemistry
How Isotope Dilution Mass Spectrometry Ensures Accurate Trace Element Quantification
Quick fact
Isotope dilution mass spectrometry is so accurate that it is a primary method of measurement: its accuracy does not depend on the yield of the chemical separation or on instrument sensitivity, because the measured ratio of two isotopes of the same element self-corrects for all losses and matrix effects.
Why this is interesting
You carefully dissolve a tiny sample, extract the element you care about, and still lose half of it during the process. How can you still know exactly how much was originally there?