Ant bait is the way to go for small ants and we prefer using gel/liquid ant baits over the granular or solid baits. Dupont does make a wonderful roach bait that we use a LOT of: Dupont Advion; didn't know they made an ant bait; I bet it is a good one. The boric acid based liquid ant baits are very good, too.
Do not spray near you baits as you will be working against yourself as the sprays are mostly repellent. The baits work slow; back off and let them eat.
I've killed every kind of ant with advion. It is very gratifying also, they can't walk past it without jumping on it an eating it. Store bought gels I've seen ants walk through without eating but if they get within 6 inches of advion they can't resist.