The Kjeldahl method or Kjeldahl digestion (Danish pronunciation: [ˈkʰelˌtɛˀl]) in analytical chemistry is a method for the quantitative determination of a sample's organic nitrogen plus ammonia/ammonium (NH 3 /NH 4 +).

The Kjeldahl method involves a three-step approach to the quantification of protein: digestion, distillation, and titration. Digestion of organic material is achieved using concentrated H 2 SO 4 , heat, K 2 SO 4 (to raise the boiling point), and a catalyst (e.g., selenium) to speed up the reaction.

Distillation: The distillation of the solution now takes place and a small quantity of sodium hydroxide is added to convert the ammonium salt to ammonia. The distilled vapours are then trapped in a special trapping solution of HCl (hydrochloric acid) and water.

2023年5月15日 · The Kjeldahl method, also known as Kjeldahl digestion, is a quantitative method for determining the nitrogen content of organic substances as well as the nitrogen content of ammonia and ammonium (\(NH_3/NH_4+\)), which are inorganic molecules.

2013年10月2日 · The Kjeldahl method was introduced in 1883 and consists of three main steps: sample digestion, distillation, and ammonia determination (titration being the primary method).

Distillation - adding excess base to the acid digestion mixture to convert NH4+ to NH3, followed by boiling and condensation of the NH3 gas in a receiving solution. Titration - to quantify the amount of ammonia in the receiving solution.

In 1883, Johan Kjeldahl introduced his "New Method for the Determination of Nitrogen in Organic Bodies", revolutionising nitrogen analysis and setting new standards. Since then, the method has become indispensable in areas such as food analysis, feed analysis, soil …

2021年5月3日 · Kjeldahl Method for Determining Nitrogen. Digestion Titration. The Kjeldahl method was developed over 100 years ago for determining the nitrogen contents in organic and inorganic substances. Although the technique and apparatus have been modified over the years, the basic principles introduced by Johan Kjeldahl still endure today.

The Kjeldahl procedure involves three major steps: The aim of the digestion procedure is to break all nitrogen bonds in the sample and convert all of the organically bonded nitrogen into ammonium ions (NH

A Kjeldahl distillation is a method which may follow a Kjeldahl digestion as part of a quantitative analysis. It is most commonly used to determine the nitrogen content in a material, for example in the analysis of proteins or rubber.