I have made a segmented for portal run, as in i have recorded the chambers seperatley so i could use my best time and then i edited it together, can i submit this?
No. These leaderboards are only for runs completed in one sitting. There are no leaderboards for segmented runs.
On that note, why can't there be leaderboards for segmented runs? Obviously segmented and single segment/RTA shouldn't be compared to each other directly, but there's no reason not to support a segmented leaderboard if there's runs being done.
In the case of Portal, I can think of several segmented runs.
There are no leaderboards for segmented run; but there are places to find the Individual Levels and you can find all the WR segmented runs on SourceRuns YouTube channel. Also, peeps4321's run is really unoptimized, even for single-segment; I think he just did a Single-Segment a day and video-edited it to cut the parts where he died. Finally, this user requested twice the same run in the speedrun.com leaderboards even thought the Portal moderators told him speedrun.com is not the place to go to publish segmented run. If you want to do a segmented run, at least try to beat current segmented runs.
There's a plenty of leaderboards with segmented runs, for example Tomb Raider games. It's simply up to mods whether they allow it or not. I don't see any reason why they shouldn't.
Portal segmented run is different than other games, a lot of segmented runs have already been made and SourceRuns decided about publishing seg runs on SourceRuns official YouTube channel.