Total Kjeldahl nitrogen (TKN) is defined as the sum of the ammoniacal nitrogen and organic nitrogen that are transformed into ammonium sulfate after mineralization.
The method (reference ICC 105/1) is applied to the determination of nitrogenous substances in cereals and products derived from them.

“Nitrogenous substances” are understood as the content of nitrogenous compounds in the product analyzed, calculated by multiplying the corresponding nitrogen content, determined by the method described, by a conventional factor. The organic substances in the sample are oxidized with concentrated sulfuric acid in the presence of a catalyst; the ammonium sulfate that forms in the reaction is treated with alkalis, and the ammonia that is released is distilled and then titrated with the Flash titrator.

FLASH automatic titrator represents the latest evolution and has been designed to satisfy a widest range of titrations with
simplicity and precision.
Flash is available in various configurations to satisfy any Client needs and has been designed to simply and precisely perform a widest range of potentiometric titrations such as: acid–base, redox, argentometric, complexometric titration.