Like any other method, the Kjeldhal procedure is subject to problems with methodology, technique and equipment. Understanding the principles behind the Kjeldahl process and using appropriate quality control procedures should prevent most problems from occurring. When developing a new or modifying an existing method, one should proceed which caution and experimental verification.
When nitrogen results differ from those expected, knowledge of common problems makes finding and correcting the error easier.
Common problems include the following: Sample size and type, Incompatibility with amounts and types of acid, salt or catalyst Used Samples, standards and reagents. Inadequate or excessive distillation, Dilution volume or aliquot volume; foaming or bumping during digestion, uneven digestion, Inadequate or excessive sample temperature, precipitation of salt or caking of digested sample, leaks in apparatus connections, Inadequate sodium hydroxide addition, Improper standardisation Instrumental and calculation errors, etc.
Thanks to the invention of Kjeldahl technique by the great Danish Scientist, Johan Kjeldahl for estimation of Nitrogen, for, there is no doubt since 1883 till now there has been no other technique to supersede Kjeldahl Chemistry inspite of several advancement in Science and Technology