UA 991 then TK 188 at Dulles
Barcelona → Washington → Istanbul
Timetable, Washington time
14:00UA 991 from Barcelona at the gate
13:30TK 188 to Istanbul leaves the gate
23 h 30 apart on the timetable, overnight
TK 188 leaves 23 h 30 after UA 991 arrives on the timetable: more than half a day, so not a connection we count.