CRM
Definition
Certified reference material. A matrix-matched material of known composition (NIST SRM 955c lead in caprine blood, SRM 1577c bovine liver) used to verify accuracy in every batch.
- Full name
- Certified reference material
- Purpose
- Verify accuracy every batch
- Example
- NIST SRM 955c, lead in caprine blood
- Example 2
- NIST SRM 1577c, bovine liver
Common questions
Why does a CRM need to be matrix-matched to the sample being tested?+
A matrix-matched material undergoes the same extraction and interference effects as the real sample, so its known concentration verifies the whole analytical method rather than just the instrument's response to a pure standard solution.
What happens if a CRM result falls outside its certified range during a run?+
The batch is flagged as out of control and results for that run are not reported until the cause is identified and corrected, since the CRM failure indicates the method was not performing within its validated accuracy for that batch.
Related terms
- AAS
- Atomic absorption spectrometry. Free ground-state atoms in a vapour absorb a characteristic resonance wavelength from a hollow-cathode lamp, and Beer-Lambert converts the...
- GFAAS
- Graphite-furnace AAS, also called electrothermal AAS. A graphite tube heated electrically through a programmed ramp atomises a microlitre aliquot, giving roughly 100...
- ICP-MS
- Inductively coupled plasma mass spectrometry: the laboratory reference method for trace element quantification in food matrices. Uses high-temperature argon plasma to atomise...
- ICP-OES
- Inductively coupled plasma optical emission spectrometry: the plasma excites atoms which emit element-specific wavelengths of light on returning to ground state; suited...
- Ion Chromatography
- Ion-exchange separation with conductivity detection after a suppressor, used to quantitate inorganic anions and cations such as fluoride, oxalate, sodium and calcium.