Kjeldahl Method of Nitrogen Determination || A Quick Review || The Channel Arc

The Kjeldahl method or Kjeldahl digestion in analytical chemistry is a method for the quantitative determination of nitrogen contained in organic substances plus the nitrogen contained in the inorganic compounds ammonia and ammonium (NH3/NH4+). Without modification, other forms of inorganic nitrogen, for instance nitrate, are not included in this measurement. This method was developed by Johan Kjeldahl in 1883.

The method consists of heating a sample at 360–410°C with concentrated sulfuric acid (H2SO4), which decomposes ("digests") the organic sample by oxidation to liberate the reduced nitrogen as ammonium sulfate. Catalysts like selenium, Hg2SO4 or CuSO4 are often added to hasten the digestion. Na2SO4 is also added to increase the boiling point of H2SO4. Digestion is complete when the liquor clarifies with the release of fumes. The end of the condenser is dipped into a known volume of standard acid (i.e. acid of known concentration). A weak acid like boric acid (H3BO3) in excess of ammonia is often used. Standardized HCl, H2SO4 or some other strong acid can be used instead, but this is less commonplace. The sample solution is then distilled with a small amount of sodium hydroxide (NaOH).[3] NaOH can also be added with a dropping funnel. NaOH reacts the ammonium (NH4+) to ammonia (NH3), which boils off the sample solution. Ammonia bubbles through the standard acid solution and reacts back to ammonium salts with the weak or strong acid. Ammonium ion concentration in the acid solution, and thus the amount of nitrogen in the sample, is measured via titration. More info about Kjeldahl Method at:
******************************************************
VIDEO MADE AVAILABLE BY:
Prodèép Nëpalënsis
FACEBOOK:
TWITTER:
INSTAGRAM:

******************************************************
IF YOU ALSO HAVE SOME WORKS OF ART THAT YOU WANT TO SHARE WITH US OR FOR MORE INFO PLEASE CONTACT:

The Channel Arc
the.channel.arc@gmail.com

FACEBOOK:
TWITTER:
INSTAGRAM:
******************************************************
PLEASE DON'T FORGET TO SUBSCRIBE OUR CHANNEL.

KJELDAHL,METHOD,NITROGEN,DETERMINATION,LAB,LABORATORY,ORGANIC,VIDEO,