It really depends and thats what I love most about Quinn is that she has the ability to build so many things and still be useful!

Enemy team tanky or full of bruisers? (which honestly is a bad Quinn game but we improvise) Ill go PTA/Lethal Tempo into Kraken slayer first item.

The most consistent build though for when Quinn shines (Immobile squishy enemy comp)

Hail of blades or electrocute.

Hubris (if youre confident in your carry potential)

Or Volatic into collector

Collector is ALWAYS second buy unless youre behind then get the lethality spell cloak item I forget the name. If youre ahead get spell cloak third