China's Liuyang Jiao set a new Olympic record on her way to winning gold in the
women's 200m butterfly.
The Beijing silver medallist raced to victory in a time of two minutes 4.06 seconds, beating Spain's Mireia Belmonte Garcia (2:05.25) into second.
"Jiao, who got the silver medal in Beijing at the age of 16, converts to gold. She had a fantastic last length, really strong. She has been around quite a while now on the international scene, even though she is just 20."
faded in the final 50m to finish sixth, while Japan's Natsumi Hoshi won the bronze medal.
Belmonte Garcia was in the lead at the turn, and looked set for gold until Jiao's late charge.
Lowe, who swims for Swansea, was well placed for a medal when she turned at halfway in third place. However, the 22-year-old could not maintain her pace and was overtaken by the fast finishers.
"It was an Olympic final and I was really happy to get into it," she said. "I gave it everything I had got but it wasn't to be.
"The crowd were brilliant. I was a bit nervous but I have had a good time in my second Olympics.
"This is definitely not my last Games. I feel like I am still young and I am looking forward to having more races."