СОВРЕМЕННЫЕ АНАЛИЗАТОРЫ ДЛЯ ОПРЕДЕЛЕНИЯ АЗОТА МЕТОДОМ КЬЕЛЬДАЛЯ

Current review covers all main stages of the quantitative determination of nitrogen by the Kjeldahl method: preparation and acid mineralization of samples, distillation, and various chemical and instrumental options for determining the ammonia released after the treatment of mineralization products with alkali. The review also describes the latest technical solutions used to improve and automate certain stages of analysis such as the usage of block and IR digesters that significantly increases the efficiency of sample mineralization and reduces its duration; the usage of automatic lifts for the mineralized samples, which reduces the work of the operator with the heavy and hot chemical samples as much as possible; the usage of autosampler, which provides the automatic transfer of mineralized samples to the distiller; the automation of distillation and titration processes; the use of software for processing the analysis results. The following technical characteristics of the basic components of automatic analyzers for the nitrogen determination by the Kjeldahl method are systematized: digesters, distillers, and titrators produced by such well-known companies as Buchi (Switzerland), C. Gerhardt, Behr Labor-Technik GmbH and FoodALYT GmbH (Germany), Foss Tecator (Denmark, Sweden), VELP Scientifica (Italy), J.P.Selecta (Spain), Hanon Instruments (China), OOO VPK Sibagropribor and OOO Vilitek (Russia). The data on the characteristics of the analyzers is also provided and includes the number and volume of test tubes (flasks), the time of mineralization, distillation and analysis, mass (volume) of the sample, and the lower limit of nitrogen detection. Keywords: Kjeldahl method, acid mineralization, distillation and quantitative determination of ammonia, automatic nitrogen analyzer DOI: http://dx.doi.org/10.15826/analitika.2019.23.2.002 (Russian) E.A. Zauer, A.B. Ershov Volgograd State Technical University, pr. Lenina, 28, Volgograd, 400005, Russian Federation