Division 5.1.1 Samples free from organic matter

Weigh to the nearest mg a sample of not more than 10 g and containing not more than 3 g of chlorine in the form of chlorides. Place with 400 ml of water in a 500 ml volumetric flask at approximately 20 ^oC. Mix for 30 minutes in the tumbler, bring up to volume, homogenise and filter.