Has anyone had a problem with the NSI trace metals amplue #2 for Sn and Ti? It is very possible that they have been preserving their Pt wrong.
NSI was not preserving the PT properly, but has since chaged preservation techniques.
Sorry, I missed this. YES! I have had several issues with NSI trace elements PTs, and the Sn/Ti was one of them. There have been several times where they had to re-do their acceptance ranges due to stability issues.
Also, because I like to keep PTs around to use as QC check samples, I will hold on to any extras that I get in and keep them until their expiry date. I had some from NSI and some from ERA and when I was going through my bin of old PT's to get rid of the old, what I noticed was that all of the ERA PTs were still crystal clear whereas every last one of the NSI PTs had formed a cloudy sediment on the bottom. This tells me that their acid forumulations are not nearly as good as ERA's are, as if they were, the stability would be as good and it is not. The sediment on those NSI PT's formed several months before the listed expiration date too, whereas some of the ERA PTs that I compared them too were actually past their expiration dates and still clear.
The other issue that I had with NSI was in regards to defects in the glass ampules. We experienced on several occasions where the glass ampule necks were defective and as a result broke in transit. It is also annoying that the ampule necks are not always wide enough to get a volumetric pipette down inside of, so many cases I would have to transfer the ampule contents into a test tube just so I could pipette it.
I know NSI is cheaper, but after all of the problems that we had, we stopped using them because the cost savings was not nearly worth all of the problems that were caused to us and were definatley not worth the risk of potential failures or loss of certification.
If you dont like ERA then give Wibby a try, as they make PTs which are just as high quality as do ERA.