Adam Peaty qualified for the men's 50m breaststroke final on day three of the World Championships, but Great Britain missed out on a medal in the final two events.
Peaty, 29, swam 26.85 seconds to qualify for Wednesday's Doha final.
Fellow Britons Lauren Cox and Kathleen Dawson finished fifth and sixth respectively in the women's 100m backstroke.
Meanwhile, Duncan Scott finished sixth in the men's 200m freestyle final on Tuesday.
The 26-year-old clocked a time of 1:45.86 in the event that won him a silver medal at the 2021 Tokyo Olympics.
Compatriot Tom Dean won gold at the event but will not compete in Qatar, and some of the world's top swimmers will not compete at the world championships, instead training for this summer's Paris Games. I chose that.
However, Dean, a two-time Olympic champion, competed briefly on Sunday as part of Great Britain's 4x100m freestyle relay team in a bid to earn an Olympic spot alongside Jacob Whittle, Matt Richards and Scott. .
Another Briton, Jack McMillan, was eliminated in his heat on Monday and did not compete in the 200m freestyle final.
Peaty, the world record holder in the 50m event, is competing at the world championships for the first time in five years after taking a break due to depression and alcohol issues.
He recorded a time of 27.23 seconds in his heat, then improved on that in the semi-finals to qualify in fourth place and go for his 12th world medal in the final.
Australia's Sam Williamson (26.41 seconds), Italy's Nicolo Martinenghi (26.65 seconds) and American Nick Fink (26.77 seconds) were the fastest to qualify.
Peaty, a three-time Olympic champion, made her return to the world stage on Monday with a bronze medal in the 100m breaststroke.
Then in the 100m backstroke, Britain's Cox swam 59.60 seconds, Dawson finished in 1:00.42, and America's Claire Curzan took gold in 58.29 seconds.
Both will also compete in Wednesday's 50m backstroke heats.
Cox, 22, won world bronze in the same event last year, while Dawson, 26, broke the world record by winning gold in Tokyo as part of Team GB's 4x100m mixed medley team.
Max Litchfield missed out on a spot in the men's 200m butterfly final, swimming a time of 1:56.93 in the semifinals and finishing 12th, four spots outside the final spot.
