The 21-year-old from Scotland raced to victory in 28.67 seconds to take 0.26 seconds off the mark set by American Jessica Galli five years ago.
There was another world record in the women's club throw F51 as American Rachael Morrison recorded 23.17 metres.
The world silver medallist eclipsed Britain's Jo Butterfield's record set in Rio last year by 36cm.
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British wheelchair racer Sammi Kinghorn has set a new world record in the 200m T53 at the Arizona Grand Prix.