Analysis by liquid chromatography coupled with mass spectrometry (LC-MS / LC-MS/MS)
Liquid chromatography-mass spectrometry (LC-MS) is a high-performance analytical method that can identify and quantify organic molecules in complex matrices with extreme precision, even at trace levels. Widely used for the analysis of residues, impurities, metabolites, and heat-sensitive compounds, LC-MS is an essential technique in the pharmaceutical, cosmetic, food, environmental, and materials sectors.
What is LC-MS / LC-MS/MS?
LC -MS (Liquid Chromatography – Mass Spectrometry) is an analytical technique that combines two complementary steps:
- chromatography (HPLC) allows the separation of the constituents of a liquid sample based on their polarity, solubility or interactions with the stationary phase.
- Mass spectrometry (MS) then allows the detection, identification and quantification of the separated molecules by measuring their exact mass and fragmentation profile .
LC-MS/MS (or tandem MS version adds a controlled ion fragmentation step, providing increased specificity and enhanced sensitivity , particularly useful for complex matrices or compounds at very low concentrations.
How the LC-MS method works
The LC-MS method follows several key steps:
- Sample preparation: dilution, filtration or extraction depending on the matrix.
- Separation by liquid chromatography (HPLC or UHPLC) : the compounds migrate at different speeds through the column, carried by the mobile phase.
- Ionization : the separated compounds are converted into ions in a suitable ionization source (ESI, APCI, etc.).
- Mass spectrometry analysis : Ions are sorted by their mass/charge ratio (m/z) in the analyzer.
- Detection and data processing : generation of mass spectra, identification by library or targeted method (MRM/SRM mode in LC-MS/MS).
Technical characteristics of LC-MS
- Detection limits : ng/g to pg/g depending on the compounds
- Types of ionization : ESI (Electrospray Ionization), APCI (Atmospheric Pressure Chemical Ionization)
- Analysis modes : full scan, targeted ion (SIM), multiple reaction monitoring (MRM)
- Qualitative and quantitative analysis
- Very high selectivity and reproducibility
- Associated standards : Ph. Eur., USP <621> and <146>, ICH Q2(R1), ISO, REACH, FCM
For which matrices?
LC -MS / LC-MS/MS applies to a wide variety of liquid, solid or complex matrices:
Main industrial applications
LC-MS and LC-MS/MS are widely used in R&D, method validation, quality control and regulatory compliance , particularly in the following sectors:
Léa Géréec
Technical and scientific advisor
