Update README.md - TODO, added empty bottle warning.

README.md

@@ -35,6 +35,7 @@ I've made a video. Its not perfect, but most of the things are covered. Bottlene
  * triphenylphosphine-oxide
 
 ### Operation procedure
+ * Check if the solvent is there (> 200ml). If not, refill with pre-mix. If pre-mix is gone, contact me or Jaya.
  * Insert your samples + blank.
  * Copy the standard sample template to your folder and personalize it.
  * Measure the samples.
@@ -62,4 +63,8 @@ Your group not in a list? **Become a MS tutor yourself!** (PhD preferred)
 ### Questions/Misc
  * If something is wrong in this guide feel free to contact me.
 
+### TODO (planned improvements)
+ * SOP is still missing
+ * Network storage
+