The use of titanium dioxide as a catalyst for large‐scale kjeldahl determination of the total nitrogen content of cereal grains

A process is described for the use of titanium dioxide as a catalyst in the Kjeldahl determination of total nitrogen, in the place of the efficient, but highly toxic mercuric oxide. The titanium dioxide is incorporated into a catalyst mixture with cupric sulphate and potassium sulphate in the ratio 0.3:0.3:10.0. Using a 1.0‐g sample, the digestion process involves the use of 20 ml of concentrated sulphuric acid, 10 g of catalyst mixture, 650‐W electric heaters and a total digestion time of 35 min. The catalyst mixture is efficient, inexpensive and non‐toxic.