US 7,462,818 B2
Determination of chemical empirical formulas of unknown compounds using accurate ion mass measurement of all isotopes
Jerry A. Zweigenbaum, Middletown, Del. (US); Earl M. Thurman, Almeria (Spain); and Imma Ferrer, Almeria (Spain)
Assigned to Agilent Technologies, Inc., Santa Clara, Calif. (US)
Filed on Nov. 04, 2005, as Appl. No. 11/267,721.
Prior Publication US 2007/0114373 A1, May 24, 2007
Int. Cl. G01N 33/48 (2006.01)
U.S. Cl. 250—282  [702/19; 702/23] 14 Claims
 
1. A method of determining an empirical formula of an analyte ion from a measured mass spectrum including a main peak and one or more isotope peaks, the method comprising:
a) comparing a relative isotopic intensity of the measured isotope peak to a calculated relative isotopic intensity of an isotopic ion of a proposed empirical formula; and
b) comparing a relative mass defect of the measured isotope peak to a calculated relative mass defect of the isotopic ion of the proposed empirical formula; and
c) identifying the proposed empirical formula as a potential candidate for the analyte ion based on the comparisons of a) and b).