Freney won the 50m Freestyle - S7 in a Paralympic record of 32.63 to add to the five golds she had already claimed.
With two events still remaining, the Australian could end up with eight medals.
I was hoping for at least one medal, but six is unbelievableJacqueline Freney
The 20-year-old said: 'I'm not a sprinter, but I'm so happy to have another medal under my belt. It's a bit of a shock actually. I was hoping for at least one medal, but six is unbelievable.
'My dad (her coach Michael) just said, "Yes, good luck and hope for the best and whatever happens on the day [happens]".
'I have a rest day tomorrow so I can recover and I am really looking forward to the 400 [freestyle]. It should be a good race. I am going to go for a world record in the 400.'
Du Toit will call time on her pioneering career after London.
The South African came in to the Games with 10 Paralympic titles and one silver and tonight's victory in the 400m Freestyle - S9 was her second of the meet along with the 100m Butterfly - S9.
The 28-year-old has not been as dominant as previously, having also been fourth and seventh in London.
Tonight she paid tribute to the Central Gauteng Aquatics president who died in January. Du Toit said: 'That race was for Cathy Doyle.
'She passed away a few months ago. She was supposed to be officiating tonight. Because she has done so much for me in my life, I just want to dedicate this medal to her and her family. Thank you to them.'
Ihar Boki claimed his fourth gold medal and fifth overall when he demolished his own world record in the 400m Freestyle - S13.
The Belarusian had promised to 'show something spectacular' after his heat swim this morning and his time of 3:58.78 took four seconds off his own world mark.
Justin Zook lowered the 100m Backstroke - S10 world record - especially impressive given he was reclassified ahead of the competition. The USA swimmer dipped 0.54 inside Andre Brasil's mark in 1:00.01.