Very early Kjeldhal digestion and distillation were performed using stone fume hoods and gas mantles as a heat source. In 1920’s this was replaced by classical Macro Kjeldhal digestion and distillation apparatus using Kjeldhal flask from 500-800ml volume.Latter variation in equipment made use of Aluminium heating blocks designed to accept number of straight digestion tubes at once simultaneously. The latest advancement in block digestion techniques by Kjeldhal procedure gave birth to automatic Nitrogen and protein analyzer in the world market from countries like Sweden, Germany, Japan, etc which made pioneering efforts for automation.
The advance Microbrilliant automatic Nitrogen /Protein Analysis system is a Pollution free and Environmental friendly system. The Hazardous acid fumes liberated during digestion are efficiently dissolved in water through giant aspiration filter pump and sent to the drain without polluting the atmosphere. The compact design of automatic block digestion with built in exhaust fume manifold system avoids the use of large fume hoods or Cupboards, saving installation cost as well as space. The instrumentation includes automatic Microprocessor based temperature controller with various built in safety features to enable a clean and a safe operation.The second stage of experiment feeds the digested sample in an automatic distillation system.The system can handle hot digestion tubes directly without the need of transferring the sample.This avoids manual spillage error during transfer, which would otherwise happen in a conventional traditional system. The Distillation process is fully programmable with precise automation and the entire process of sample dilution, reagent addition, steam injection, Boric acid addition, residue removal, water refilling, goes unhindered with a single start operation and it takes not more than 3 to 6 minutes for the completion of distillation.The third stage of the equipment a titration phase is simple and easy to handle with conventional glass burette titration system by any user. Alternatively the user may go in for a fully automatic distillation system with online integrated Auto Titration system with PC interface.
The methodology of analysis may vary slightly based on the sample behaviour. One may choose a 100ml microdigestion system for samples which are not violent in nature.
High Protein samples create high effervescence and frothing and hence require a Macro digestion system of 250ml capacity. The Soil Samples have very low Nitrogen content and hence one needs at least 2 to 5gms of sample for analysis for which a Macrodigestion system is a must. A Technical expert or Chemist would recommend the appropriate use of catalyst, temperature of digestion, acid salt-ratio and so on. The only reliable method of determination of protein is through determination of Nitrogen by formula conversion i.e. 1mg nitrogen equals 6.25 mg protein. In other words 100mg of protein contains 16mg Nitrogen. Hence Nitrogen value multiplied by 6.25 factor gives percentage of protein. Thus the only standard method of determination of protein is through Kjeldhal Nitrogen method.