Relative quantitation can be achieved through spectral counting, isobaric labeling with either TMT or ITRAQ tags, or through SILAC metabolic labeling. If you submit labeled samples, your submission must include the appropriate isotopic label information such as the product data sheet included in your labeling kit.
We strongly urge our users to have experience with sample preparation for mass spectrometry before attempting quantitation with labeling techniques. Contact us for details.