[Melissa]

I am studying the preservation of samples of water by constituent. I am reading and understanding the table 1060 I in the Standard methods ed 23th. The last columns of table are: 1) preservation 2)Maximum Storage Recommended 3)Regulatory

In case of the determination of alkalinity in water:

Preservation                                Maximum Storage Recommended                           Regulatory
  Cool, >=6°C                                                          24 h                                                                   14 d

In my experience, I must determinate the alkalinity in  the samples in the next 24 hours but what it means "regulatory in 14 days"?
Thanks a lot.
I apologize, I am learning english

[Melissa]

I consider that regulatory could apply just in an extremely case of postpone the analysis.

[Melissa]

Maybe it could be that water samples are sealed and do not open for the next 14 days  and preserved at 4°C.
I am trying to explain my point of view about it

[Arkcon]

I have never used this standard, and I'm sorry you haven't had more help so far.  You have read a table, and one part of it is unclear, even contradictory.  Or at least your conclusions are contradictory.  What does the text of the standard say.  Either cover to cover, or at least near this table.  Maybe its all clear when you study carefully? 

Maybe another expert in the field can help you?  Maybe the customer has an idea?  Or the regulatory body the you're reporting the results to has an idea?  Why are you following this standard -- who told you to do it, and who is checking that you are following it?  These are questions for an analytical chemist -- why we do things is just as important as how.

As a wild guess, the 14 days storage might mean you must keep the sample 14 days after you have tested it, in case there is an anomaly, so you can recheck.  You can't use the result of the 14 day sample, but you keep it as a check of the work.  That's something common in analytical testing.  But really, I'm guessing wildly here.