This topic is getting famous and important and I think the only accurate way is to perform a quick investigation at our hospitals for the content we use individually and precisely. I think hospital Lab can do it, as long as they have the mechanism to measure trace elements in blood, I think they can do it for TPN contents.
https://mega.nz/file/OxgmiDQR#Byuk5OEJssDHfKsRL_0Qzf-Dxu-iIN0I8BtZcQeEYdI
