Officers responded to a report of a substance being thrown over the victim in the doorway of a property in Steine Gardens around 4.20pm on Thursday 20 May.
The woman in her 20s, was taken to hospital where she remains with potentially life changing injuries.
Detectives arrested the 25-year-old man on Saturday (29 May) on suspicion of causing grievous bodily harm and he remains in custody.
Anyone who has information which could help our investigation into the assault should report online or ring 101 quoting Operation Overstone.
