Accounts are limited to 35 nodes in one instance of the map, with a hard cap at 50 for one day.

The "Return to..." achievements for Lake Doric will provide 250 iirc.

It's not much extra per day, but don't forget about https://wiki.guildwars2.com/wiki/Jade_Fragment_Node in the home instance (or homestead). You can even harvest another player's and save the 50 gold for buying it.

You might know this already, but if you run out on one character you can switch characters and get more again (up to that cap the other person mentioned). If you get the portal tome and put it in a shared inventory slot it makes it a breeze to switch.