diff --git a/doc/tutorials/12-constant_pH/CMakeLists.txt b/doc/tutorials/12-constant_pH/CMakeLists.txt
index fd65e397967..e4fe6fe1f40 100644
--- a/doc/tutorials/12-constant_pH/CMakeLists.txt
+++ b/doc/tutorials/12-constant_pH/CMakeLists.txt
@@ -1,4 +1,5 @@
 configure_file(12-constant_pH.ipynb ${CMAKE_CURRENT_BINARY_DIR}/12-constant_pH.ipynb COPYONLY)
+configure_file(si_units.py ${CMAKE_CURRENT_BINARY_DIR}/si_units.py COPYONLY)
 
 add_custom_target(tutorials_12)