LC-MS/MS MRM
Definition
Liquid chromatography with triple-quadrupole tandem mass spectrometry operated in multiple reaction monitoring mode. The most sensitive confirmatory method for melamine (primary MRM transition m/z 127.1→85.1 in positive ESI mode, LOQ 10 ppb in milk).
- Instrument
- Triple-quadrupole LC-MS/MS
- Mode
- Multiple reaction monitoring
- Target
- Melamine in milk
- MRM transition
- m/z 127.1→85.1, positive ESI
Common questions
What does multiple reaction monitoring add over a standard scan?+
MRM tracks only pre-selected parent-to-fragment ion transitions rather than scanning the full mass range, which cuts background noise sharply and lets the instrument detect a target compound at much lower concentrations with high confidence in complex matrices like milk.
Why was melamine testing scaled up after 2008?+
Melamine was added to dilute milk and infant formula to inflate apparent protein content on crude nitrogen-based tests, causing kidney injury in infants. LC-MS/MS MRM became a standard confirmatory method because it identifies melamine directly rather than inferring protein from total nitrogen.
Related terms
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- The FAO/WHO joint food standards programme that sets international reference limits. Its 2012 action levels for melamine (2.5 mg/kg in infant formula,...
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- Melamine
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