Patent ID: 6875618

Claim:
A method for detecting and measuring the degree of phosphorylation in a sample, comprising: (i) introducing the sample containing a phosphorylated analyte into a low resolution inductively coupled plasma mass spectrometer having a reactive collision cell, and producing analyte ions; (ii) reacting the analyte ions with a reactive gas, producing product ions with a different mass to charge ratio than the analyte ions which provides interference-free detection; (iii) detecting and measuring a signal or combination of signals from a product phosphorus-containing ion and a signal or combination of signals from a second ion, wherein the second ion is specific to the sample and is one of an ion and a plurality of ions; and (iv) computing one of the ratio and plurality of ratios, of the signal or combination of signals from the product phosphorus-containing ions to the signal or combination of signals from the second ions, to determine the degree of phosphorylation in the sample.