Label-free quantification is an important mass spectrometry method that requires no specific sample labelingInstead, it utilized MS/MS generated signals of specific peptides for comparison to define protein expression modifications between samples. Two alternative label-free quantification strategies are frequently used. Spectra Count (SC) and peptide ion intensities measurements (a.k.a, lC, extracted ion chromatography)with the latter being more accurate and widely used. Label-free quantification requires highly stable and reproducible liquid chromatography with tandem mass spectrometry (LC-MS-MS) and has no requirement for expensive isotopes for labelling.