diff --git a/src/MSDIAL5/MsdialCore/Utility/DataObjConverter.cs b/src/MSDIAL5/MsdialCore/Utility/DataObjConverter.cs
index 10fe54a76..d5800c669 100644
--- a/src/MSDIAL5/MsdialCore/Utility/DataObjConverter.cs
+++ b/src/MSDIAL5/MsdialCore/Utility/DataObjConverter.cs
@@ -163,6 +163,7 @@ public static void SetRepresentativeProperty(AlignmentSpotProperty spot) {
             spot.TimesMin = alignedPeaks.Argmin(peak => peak.ChromXsTop.Value).ChromXsTop;
             spot.TimesMax = alignedPeaks.Argmax(peak => peak.ChromXsTop.Value).ChromXsTop;
 
+            spot.MassCenter = alignedPeaks.Argmax(peak => peak.PeakHeightTop).Mass;
             spot.MassMin = (float)alignedPeaks.Min(peak => peak.Mass);
             spot.MassMax = (float)alignedPeaks.Max(peak => peak.Mass);
 
@@ -172,10 +173,9 @@ public static void SetRepresentativeProperty(AlignmentSpotProperty spot) {
                 MainType = chromXType,
                 RT = new RetentionTime(alignedPeaks.Average(peak => peak.ChromXsTop.RT.Value), representative.ChromXsTop.RT.Unit),
                 RI = new RetentionIndex(alignedPeaks.Average(peak => peak.ChromXsTop.RI.Value), representative.ChromXsTop.RI.Unit),
-                Mz = new MzValue(alignedPeaks.Average(peak => peak.ChromXsTop.Mz.Value), representative.ChromXsTop.Mz.Unit),
+                Mz = new MzValue(spot.MassCenter, representative.ChromXsTop.Mz.Unit),
                 Drift = new DriftTime(alignedPeaks.Average(peak => peak.ChromXsTop.Drift.Value), representative.ChromXsTop.Drift.Unit),
             };
-            spot.MassCenter = alignedPeaks.Max(peak => (peak.ChromXsTop.Value, peak.Mass)).Mass;
         }
 
         public static int GetRepresentativeFileID(IReadOnlyList<AlignmentChromPeakFeature> alignment) {