Prep it in the morning and have it at work to drink throughout the day!
Aluminum works best, I don’t know why. Normally (any other material) the goodness is half gone in a day (so use anything you like). Aluminum holds it for and additional day (goodness half gone in two days).
Keeping it cool also helps retain the ‘goodness’. Conversely, heating the bubbled water (like to make tea) drives the goodness away.