Analysis of mass spectral data in the quiet zones

A method comprising:

• a) summing the intensity of a representative number of fragmentation spectra obtained for a selected analyte to thereby obtain a composite spectrum;
• b) determining one or more quiet zones in the composite spectrum;
• and c) selecting one or more labeling reagents that, when used to label the selected analyte, will fragment in a mass spectrometer to produce at least one label fragment ion having a mass to charge ratio located in one of the quiet zones of the composite spectrum.

(canceled)

40-43. (canceled)

45-46. (canceled)

64-82. (canceled)

A method comprising:

• a) summing the intensity of a representative number of fragmentation spectra obtained for two or more selected analytes to thereby obtain a composite spectrum for the two or more analyte types;
• b) determining one or more quiet zones in the composite spectrum;
• and c) selecting one or more labeling reagents that, when used to label the selected analytes, will fragment in a mass spectrometer to produce at least one label fragment ion having a mass to charge ratio located in one of the quiet zones of the composite spectrum.

(canceled)

A method comprising:

• a) selecting one or more labeling reagents that, when used to label a selected analyte, will fragment in a mass spectrometer to produce at least one label fragment ion having a mass to charge ratio located in a quiet zone of a composite spectrum b) labeling the selected analyte with the selected one or more labeling reagents;
• c) detecting in a mass spectrometer a label fragment ion produced by fragmentation of the labeled analyte in the mass spectrometer wherein the label fragment ion has a mass to charge ratio located in one of the quiet zones of the composite spectrum.