diff --git a/src/nplinker/metabolomics/gnps/gnps_spectrum_loader.py b/src/nplinker/metabolomics/gnps/gnps_spectrum_loader.py
index 0a126242..7860ea5d 100644
--- a/src/nplinker/metabolomics/gnps/gnps_spectrum_loader.py
+++ b/src/nplinker/metabolomics/gnps/gnps_spectrum_loader.py
@@ -89,8 +89,8 @@ def _load(self):
                 intensity=list(spec["intensity array"]),
                 precursor_mz=precursor_mz,
                 rt=rt,
+                metadata=spec["params"],
             )
-            spectrum.metadata = spec["params"]
             self._spectra.append(spectrum)
 
     def _get_precursor_charge(self, charges: list) -> int: