--- a/GCMS/combine_output.xml	Thu Mar 19 15:04:56 2015 +0100
+++ b/GCMS/combine_output.xml	Fri Mar 20 17:10:04 2015 +0100
@@ -17,6 +17,10 @@
   <help>
 Performs a combination of output files from the 'RankFilter' and 'Lookup RI for CAS' tools into two tab-separated files.
 
+Merges data from both input dictionaries based on the Centrotype field.
+In the 'RIQC-RankFilter output' the centrotype is found in the 'ID' field (first part before the "-"). In the 'RIQC-Lookup RI for CAS output'
+the centrotype is found in the 'Centrotype' field. 
+
 The files produced are contain either all hits for a compound on a single line (Single) or on separate lines 
 (Multi).