This book provides a comprehensive survey of the Kjeldahl method and its modifications. It covers all relevant topics, including sample digestion and its variables, distillation and determination of ammonia, equipment development, and concludes with a review of the literature published on the method. Since its introduction in 1883, the Kjeldahl method has been an essential analytical tool for nitrogen determination in research, academic and industrial laboratories. This makes the history of the Kjeldahl method of outstanding relevance to graduate students, postgraduate students, researchers, teachers, and laboratory staff in the fields of analytical chemistry, food/feed analysis, animal/human nutrition, soil/water analysis, and so forth.
"This method has probably been applied in one modification or another to every possible form of nitrogen, and in perhaps more laboratories than almost any other single type of analytical method" (Kirk, 1950).
Author(s): Jaime Aguirre
Publisher: Springer
Year: 2023
Language: English
Pages: 150
City: Cham
Preface
Acknowledgements
Contents
About the Author
1 Introduction
References
2 A Brief History of Organic Elemental Analysis
2.1 Carbon and Hydrogen Analysis
2.2 Nitrogen Analysis
References
3 Nitrogen Compounds
3.1 The Kjeldahl Method Applied to Different Nitrogen Compounds
References
4 The Kjeldahl Method
4.1 Digestion
4.1.1 Acid Requirements and Temperature
4.1.2 Catalysts and Salt Addition
4.1.3 Hydrogen Peroxide
4.1.4 Sealed Tube Digestion
4.1.5 Microwave Digestion
4.2 Ammonia Distillation and Determination
4.2.1 Titration
4.2.2 Spectrophotometry
4.2.3 Chromatography
4.2.4 Ammonium Ion-Selective Electrode
References
5 The Advancement of Kjeldahl Equipment
5.1 Early Devices
5.2 The Caustic Splash Problem
5.3 The Ammonia Distillation Equipment
5.4 Solving the Problem of Fumes Disposal
5.5 The Small Details: Racks and Stands
5.6 The Miniature Equipment: Micro-Kjeldahl Devices
5.7 Kjeldahl Equipment Today
References
6 Experimental: Evaluation of Titanium Dioxide as a Catalyst in the Determination of Nitrogen by the Kjeldahl Method
6.1 Introduction
6.2 Acid-to-Salt Ratio
6.3 Catalyst
6.4 Experimental
6.5 Production of a Catalytic Mixture
References
7 Important Topics Related to the Kjeldahl Method
7.1 The Carlsberg Foundation and the Carlsberg Research Laboratory
7.2 Nitrogen-to-Protein Conversion Factors
7.3 Reference Materials and Primary Standards
7.4 Food Standards and the Kjeldahl Method
7.5 Patents on Kjeldahl Equipment
7.6 Reviews of the Kjeldahl Method
7.7 A Comparison of the Kjeldahl and Dumas Methods
7.8 Other Methods for Nitrogen Determination Developed in the 1900s
References
