What breaks Wudu exactly? (Quran references only)

I've been doing some research on what would break or nullify Wudu, but the answers never have references to the Quran. In what ayah(s) does it state what breaks Wudu? The reply I am looking for would only consist of Quran references; please refrain from answers that rely on hadiths or third-party explanations of God's verses.