diff --git a/src/scgenerator/io.py b/src/scgenerator/io.py
index 18f6fea..cc316c3 100644
--- a/src/scgenerator/io.py
+++ b/src/scgenerator/io.py
@@ -233,7 +233,7 @@ class DataFile:
 
     def load_arrays(self, *labels: str | tuple[str, ...]) -> tuple[np.ndarray, ...]:
         raw_data = self.load_bytes()
-        extension = self.path.lower().split()[-1]
+        extension = self.path.lower().split(".")[-1]
         if extension == "npz":
             df = np.load(BytesIO(raw_data))
             return load_npz_data(df, *labels)