Zinc oxide is the metal zinc that has been oxidized. The chemical formula is ZnO, 1 zinc atom and 1 oxygen atom held together by an ionic bond. Zinc oxide does occur in nature as the mineral zincite, but it is quite rare and commercially unavailable.
I have done a few stool samples in my time and have always just stored them in the fridge, until the next day to take them into the docs. Good luck hun I hope they get it sorted.
You can store properly prepared powdered formula for a healthy full term baby in a refrigerator for 24 hours. This formula should be prepared in a sterilized bottle and cooled to room temperature (usually by holding it under cold, running water).