Insanity Guide (I played as Sentinel class)
The availability of Stasis power can make this battle almost trivial.
Max out Liara's Stasis until you reach Enhanced Stasis. Liara's Warp power is also useful for destroying Barrier.
Stasis is unique among all the powers in that it will work despite any defensive layers that an enemy has (including barrier) - knowing this you should use Stasis repeatedly on this boss. She will freeze in place and can take no damage, so there is no point in shooting her yet.
Once Stasis wears off, she will fall to the ground briefly, where she will receive bonus damage (x3 to x4). As she is getting up use this small window of time to shoot repeatedly and fire warp at her.
One she stands up apply stasis again. Repeat until you beat her.