What is the principle of LC-MS quantification?
LC-MS (Liquid Chromatography-Mass Spectrometry) is an analytical technique that combines liquid chromatography (LC) with mass spectrometry (MS). The principle of LC-MS quantification includes the separation of samples by liquid chromatography and the detection and quantification of separated components by mass spectrometry. The main steps of the LC-MS quantification principle are as follows:
1. Liquid Chromatography Separation:
In an LC-MS system, the components in the sample are first separated using liquid chromatography. Liquid chromatography achieves separation through different stationary phases, mobile phases, and gradient elution programs. The effectiveness of the separation depends on factors such as the chromatographic column, mobile phase, and elution conditions.
2. Electrospray Ionization:
After separation by liquid chromatography, the sample solution is delivered to the ion source of the mass spectrometer. In bioanalysis, the most commonly used ionization method is electrospray ionization (ESI). Electrospray ionization converts the sample solution into charged aerosols, and the sample molecules or ions in the aerosols are then introduced into the mass spectrometer.
3. Mass Spectrometry Detection:
Once inside the mass spectrometer, the sample ions are separated by a mass analyzer (such as a quadrupole, time-of-flight, or orbitrap) based on their mass-to-charge ratio (m/z). The ion signal intensity detected by the mass spectrometer is proportional to the concentration of the sample. By measuring the signal intensity of target ions, quantitative analysis of the components in the sample can be achieved.
4. Quantification Strategy:
LC-MS quantification typically employs external standard methods, internal standard methods, or multi-point calibration methods. In the external standard method, standard curves are plotted by measuring standards of known concentrations, and the concentration is calculated based on the signal intensity of the sample to be measured. The internal standard method involves adding an isotopically labeled internal standard of known concentration, which can correct errors in sample preparation and analysis, improving the accuracy and precision of quantification. The multi-point calibration method involves establishing a multi-point calibration curve at different concentration levels, making the quantification results more reliable.
In summary, the principle of LC-MS quantification includes liquid chromatography separation, ionization, mass spectrometry detection, and quantification strategies. By measuring and calculating the signal intensity of target components, accurate and precise quantitative analysis can be achieved.
BiotechPack, A Biopharmaceutical Characterization and Multi-Omics Mass Spectrometry (MS) Services Provider
Related Services:
Quantitative Proteomics Analysis
Label-Free Quantitative Proteomics Analysis
Label-Based Protein Quantification Techniques - iTRAQ, TMT, SILAC
How to order?
