using the real C12 C13 mass difference to compute isotope masses

src/fr/inra/pappso/xtandempipeline/Utils.java

@@ -47,6 +47,10 @@ public class Utils {
 	 */
 	public static double mhelectron = (double) 1.007825035;
 
+	public static double mDeltaC12C13 = (double) 1.0033548378;
+
+	public static double mneutron = (double) 1.0086655;
+
 	public static double onemillion = (double) 1000000;
 
 	static private String getPappsoGroupingId(Integer num) {

src/fr/inra/pappso/xtandempipeline/filter_print/calculation_peptide_mh_deviation.java

@@ -28,7 +28,7 @@ public class calculation_peptide_mh_deviation extends calculation_base_peptide {
 			double diff = pep.get_mhplus_theo() - pep.get_mhplus_obser();
 			if (is_ppm) {
 				while (diff < -0.5) {
-					diff = diff + (double) Utils.mhelectron;
+					diff = diff + (double) Utils.mDeltaC12C13;
 				}
 				diff = (diff / pep.get_mhplus_theo()) * Utils.onemillion;
 			}