diff --git a/prosit_data_merge.py b/prosit_data_merge.py
index 1211691f84bfc89365ff2e314231465457e65752..d864658ab74243be7f8c41af195bdbb3e700fc82 100644
--- a/prosit_data_merge.py
+++ b/prosit_data_merge.py
@@ -150,7 +150,8 @@ df = pd.read_pickle('database/data_prosit_merged_holdout.pkl')
 
 print(len(df))
 print(df.head())
-df = df[df['Retention time']!=[0,0,0,0,0,0]]
+df['Retention time']=df['Retention time'].apply(lambda x : x[0])
+df = df.loc[df['Retention time']!=0]
 print(len(df))
 print(df.head())