ISO 2751:1973

Urea for industrial use — Determination of the buffer coefficient — Potentiometric method

Applicable to solutions of conventional concentration. The principle consists in measurement, at (20 0.5) 0C, of the quantity of 0.05 N acid solution required to effect a pH change from 8 to 6 for a solution containing 100 g of urea in 1000 ml of solution. For the measurement a pH meter is used fitted with a glass electrode and a calomel electrode. The method has also been approved by the IUPAC.