I suppose it would work. Larger would probably work too.
http://forums.ppsspp.org/showthread.php?tid=14237
If I were you, I'd just get the dual slot (it's cheap and you can use only one.) Otherwise, I'd contact the maker of the adapter you're planning to get, and ask them. If it doesn't work, it'd be because the adapter doesn't support it somehow.
-[Unknown]
http://forums.ppsspp.org/showthread.php?tid=14237
If I were you, I'd just get the dual slot (it's cheap and you can use only one.) Otherwise, I'd contact the maker of the adapter you're planning to get, and ask them. If it doesn't work, it'd be because the adapter doesn't support it somehow.
-[Unknown]