Claim: UAN has three solution grades of 28, 30, and 32 which are made up of 40, 42, and 45 percent ammonium nitrate respectively.
Evidence: The most commonly used grade of these fertilizer solutions is UAN 32.0.0 (32%N) also known as UN32 or UN-32, which consists of 45% ammonium nitrate, 35% urea and only 20% water. Other grades are UAN 28, UAN 30 and UAN 18.